diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/media/Mdt.kt b/android/app/src/main/kotlin/com/mag160c/thermal/media/Mdt.kt
index cc3fc54..101a70d 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/media/Mdt.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/media/Mdt.kt
@@ -13,9 +13,18 @@ import java.io.ByteArrayOutputStream
  * DDT body = typed blocks {u32 magic, u32 len, data padded to 4}:
  *   0x5BB5B55B camera info (0x38B from command 66b)
  *   0x5BB5B55C second info block (0x38B from 66c, optional)
- *   0x5BB5B55D raw measurement frame (19200 x uint16 LE)
+ *   0x5BB5B55D raw measurement frame (19200 x uint16 LE) — RAW sensor response
  *   0x5BB5B55E text note (UTF-8, optional)
  *   0x5BB5B55F probe points (UTF-8 lines "x,y,label,tempMc", optional)
+ *   0x5BB5B560 NUC counts in PHOTO coordinates (19200 x uint16 LE, optional)
+ *
+ * WHY THE NUC BLOCK EXISTS (2026-09-11): the raw frame is the sensor response
+ * BEFORE non-uniformity correction, so converting it directly yields nonsense
+ * (the analysis panel showed 145 C max / -161 C min for a 30 C scene). The live
+ * readouts use the pipeline's NUC output (counts), which is what the calibration
+ * tables are valid for. The photo therefore carries that corrected data, already
+ * transformed into the saved photo's own pixel order, so an offline temperature
+ * lookup is a plain index into it and gives the same numbers the live view showed.
  */
 object Mdt {
     const val SECTION_DDT = 0x5BB5B55B
@@ -27,12 +36,17 @@ object Mdt {
     const val BLOCK_TXT = 0x5BB5B55E
 
     /**
-     * Probe points captured with the photo. Stored as UTF-8 text ("x,y,label,tempMc"
-     * per line) so the values stay inspectable with any hex editor — the same
-     * reasoning the vendor layout uses for its TXT section.
+     * Probe points captured with the photo, in the SAVED PHOTO's pixel
+     * coordinates (not sensor coordinates — that mismatch put the markers in the
+     * wrong place when the photo was displayed). Stored as UTF-8 text
+     * ("x,y,label,tempMc" per line) so the values stay inspectable with any hex
+     * editor — the same reasoning the vendor layout uses for its TXT section.
      */
     const val BLOCK_PROBES = 0x5BB5B55F
 
+    /** NUC (calibrated) counts in photo pixel order; see the header note. */
+    const val BLOCK_NUC = 0x5BB5B560
+
     /** One probe carried in an MDT file. */
     data class Probe(val x: Int, val y: Int, val label: String, val tempMc: Int)
 
@@ -84,6 +98,7 @@ object Mdt {
         framePixels: ByteArray?,
         text: ByteArray? = null,
         probes: ByteArray? = null,
+        nucPixels: ByteArray? = null,
     ): ByteArray {
         val out = ByteArrayOutputStream(align4(jpg.size) + 0x88 + 38400 + 320)
         out.write(jpg, 0, jpg.size)
@@ -107,6 +122,7 @@ object Mdt {
         }
         text?.let { emit(BLOCK_TXT, it) }
         probes?.let { if (it.isNotEmpty()) emit(BLOCK_PROBES, it) }
+        nucPixels?.let { if (it.size == 38400) emit(BLOCK_NUC, it) }
 
         val bodyBytes = body.toByteArray()
         val header = ByteArray(0x88)
@@ -153,6 +169,7 @@ object Mdt {
             // block payloads are padded to 4; strip the NUL padding
             text = blocks[BLOCK_TXT]?.let { String(it, Charsets.UTF_8).trimEnd('\u0000') },
             probes = parseProbes(blocks[BLOCK_PROBES]),
+            nucPixels = blocks[BLOCK_NUC],
         )
     }
 
@@ -177,10 +194,23 @@ object Mdt {
         val jpg: ByteArray,
         val info0: ByteArray?,
         val info1: ByteArray?,
-        /** Raw 38400 B measurement frame (19200 x u16 LE), null when absent. */
+        /**
+         * Raw 38400 B sensor response (19200 x u16 LE). NOTE: this is PRE-NUC
+         * data — do not convert it to temperature directly (see [nucPixels]).
+         */
         val framePixels: ByteArray?,
         val text: String?,
-        /** Probe points stored with the photo (empty when none). */
+        /** Probe points in the saved photo's pixel coordinates (empty when none). */
         val probes: List<Probe> = emptyList(),
-    )
+        /**
+         * Calibrated NUC counts in the saved photo's pixel order (19200 x u16 LE),
+         * valid input for TempMath.countsToTempMc. Null for photos taken before
+         * 2026-09-11 — callers must then refuse to show temperatures rather than
+         * computing wrong ones.
+         */
+        val nucPixels: ByteArray? = null,
+    ) {
+        /** True when this photo can be measured offline. */
+        val hasTemperatureData: Boolean get() = nucPixels != null
+    }
 }
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/media/MdtProbe.kt b/android/app/src/main/kotlin/com/mag160c/thermal/media/MdtProbe.kt
new file mode 100644
index 0000000..a802c06
--- /dev/null
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/media/MdtProbe.kt
@@ -0,0 +1,21 @@
+package com.mag160c.thermal.media
+
+import android.content.Context
+import android.net.Uri
+
+/**
+ * Cheap "can this photo be measured offline?" check for the analysis list.
+ *
+ * A measurable photo carries the NUC block (see [Mdt.BLOCK_NUC]). Only the tail
+ * and the DDT block table are read — never the whole file — so filtering a large
+ * album stays fast.
+ */
+object MdtProbe {
+    fun isMeasurable(context: Context, uri: Uri): Boolean = runCatching {
+        context.contentResolver.openInputStream(uri)?.use { input ->
+            val all = input.readBytes()
+            val parsed = Mdt.parse(all) ?: return@use false
+            parsed.hasTemperatureData
+        } ?: false
+    }.getOrDefault(false)
+}
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/media/PhotoSaver.kt b/android/app/src/main/kotlin/com/mag160c/thermal/media/PhotoSaver.kt
index dbfcd62..6681ebe 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/media/PhotoSaver.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/media/PhotoSaver.kt
@@ -27,9 +27,126 @@ object PhotoSaver {
 
     fun fileName(now: Date = Date()): String = "MAG160C_${TIME_FMT.format(now)}.jpg"
 
-    /** Probe annotation burned into a saved photo. */
+    /** Probe annotation burned into a saved photo (photo pixel coordinates). */
     data class ProbeMark(val x: Int, val y: Int, val label: String, val tempC: Float)
 
+    /**
+     * Marker geometry relative to the IMAGE, not to screen density.
+     *
+     * The first version sized markers with screen density (4.5*density dot,
+     * 9*density ring) while drawing into a 320x240 bitmap, so the rings came out
+     * ~36 px across on a 320 px-wide photo — enormous (the user's "测温点太大了").
+     * Sizes are now derived from the image width, keeping the same proportion the
+     * live screen shows.
+     */
+    private class MarkStyle(imageWidth: Int) {
+        val scale = imageWidth / 320f
+        val dotR = 2.6f * scale
+        val ringR = 5.5f * scale
+        val ringW = 1.4f * scale
+        val textSize = 9f * scale
+        val labelGap = 7f * scale
+        val shadow = 1.5f * scale
+    }
+
+    /**
+     * Build the NUC block for a photo: ONE count per photo pixel, so an offline
+     * lookup is literally `counts[iy * photoWidth + ix]`.
+     *
+     * Why 1:1 with the photo and not the 160x120 sensor grid: the photo is
+     * displayed in its own pixel space, and any attempt to keep a smaller grid
+     * forces every caller to re-derive the rotation/flip/upscale — the exact class
+     * of index confusion that produced both wrong temperatures and misplaced
+     * markers. Costs 4x the bytes (153 KB) and removes the ambiguity entirely.
+     */
+    fun buildPhotoOrderedCounts(
+        nuc160: IntArray,
+        orientation: Orientation,
+        srcW: Int = 320,
+        srcH: Int = 240,
+    ): IntArray {
+        require(nuc160.size >= 160 * 120) { "expected 19200 NUC samples, got ${nuc160.size}" }
+        val rot = ((orientation.rotateDeg % 360) + 360) % 360
+        val outW = if (rot % 180 == 0) srcW else srcH
+        val outH = if (rot % 180 == 0) srcH else srcW
+        val out = IntArray(outW * outH)
+        for (iy in 0 until outH) {
+            for (ix in 0 until outW) {
+                val s = photoToSensor(ix, iy, srcW, srcH, rot, orientation)
+                out[iy * outW + ix] = nuc160[s[1] * 160 + s[0]]
+            }
+        }
+        return out
+    }
+
+    /**
+     * Photo pixel -> SENSOR pixel: the exact inverse of the transform
+     * [encodeRendered] applies to the bitmap (flips, then clockwise rotation) with
+     * the 2x upscale in between.
+     *
+     * Buffer coords come from the documented forward map
+     *   rot 0   (bx,by) -> (bx, by)          rot 180 -> (W-bx, H-by)
+     *   rot 90  (bx,by) -> (H-by, bx)        rot 270 -> (by, W-bx)
+     * inverted below; then the flips are undone, then the 2x upscale.
+     */
+    fun photoToSensor(
+        ix: Int,
+        iy: Int,
+        srcW: Int = 320,
+        srcH: Int = 240,
+        rot: Int,
+        orientation: Orientation,
+    ): IntArray {
+        val W = srcW
+        val H = srcH
+        var bx: Int
+        var by: Int
+        when (((rot % 360) + 360) % 360) {
+            90 -> {
+                bx = iy
+                by = H - ix
+            }
+            180 -> {
+                bx = W - ix
+                by = H - iy
+            }
+            270 -> {
+                bx = W - iy
+                by = ix
+            }
+            else -> {
+                bx = ix
+                by = iy
+            }
+        }
+        if (orientation.flipH) bx = W - bx
+        if (orientation.flipV) by = H - by
+        val sx = (bx / 2).coerceIn(0, 159)
+        val sy = (by / 2).coerceIn(0, 119)
+        return intArrayOf(sx, sy)
+    }
+
+    /** Pack an IntArray of counts as u16 little-endian. */
+    fun countsToBytes(counts: IntArray): ByteArray {
+        val out = ByteArray(counts.size * 2)
+        for (i in counts.indices) {
+            val v = counts[i].coerceIn(0, 0xFFFF)
+            out[i * 2] = (v and 0xFF).toByte()
+            out[i * 2 + 1] = ((v shr 8) and 0xFF).toByte()
+        }
+        return out
+    }
+
+    /** Unpack u16 little-endian bytes into counts. */
+    fun bytesToCounts(bytes: ByteArray): IntArray {
+        val n = bytes.size / 2
+        val out = IntArray(n)
+        for (i in 0 until n) {
+            out[i] = (bytes[i * 2].toInt() and 0xFF) or ((bytes[i * 2 + 1].toInt() and 0xFF) shl 8)
+        }
+        return out
+    }
+
     /**
      * Orientation applied to a saved photo, mirroring what the live view showed
      * (the image is locked to the portrait frame plus the user's manual
@@ -106,41 +223,61 @@ object PhotoSaver {
 
         if (probes.isNotEmpty()) {
             val canvas = Canvas(outBmp)
+            val s = MarkStyle(outW)
+            // Probes are given in PHOTO pixel coordinates already (the capture
+            // converts them together with the NUC data), so no extra transform.
             val ring = Paint(Paint.ANTI_ALIAS_FLAG).apply {
                 color = Color.WHITE
                 style = Paint.Style.STROKE
-                strokeWidth = 2.5f * density
-                setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+                strokeWidth = s.ringW
+                setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
             }
             val dot = Paint(Paint.ANTI_ALIAS_FLAG).apply {
                 color = Color.WHITE
                 style = Paint.Style.FILL
-                setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+                setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
             }
             val text = Paint(Paint.ANTI_ALIAS_FLAG).apply {
                 color = Color.WHITE
-                textSize = 13f * density
+                textSize = s.textSize
                 typeface = Typeface.SANS_SERIF
-                setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+                setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
             }
             for (p in probes) {
-                val pos = sensorToImage(p.x, p.y, w, h, rot, orientation)
-                val sx = pos[0].toFloat()
-                val sy = pos[1].toFloat()
-                canvas.drawCircle(sx, sy, 4.5f * density, dot)
-                canvas.drawCircle(sx, sy, 9f * density, ring)
-                val label = (if (p.label.isNotEmpty()) "${p.label} " else "") +
-                    "%.1f℃".format(p.tempC)
-                val tw = text.measureText(label)
-                var tx = sx + 13f * density
-                if (tx + tw > outW - 2f * density) tx = sx - 13f * density - tw
-                val ty = (sy + text.textSize).coerceAtMost(outH - 4f * density)
-                canvas.drawText(label, tx, ty, text)
+                val sx = p.x.toFloat()
+                val sy = p.y.toFloat()
+                drawMarker(canvas, sx, sy, p.label, p.tempC, s, ring, dot, text, outW, outH)
             }
         }
         return encodeJpeg(outBmp, quality)
     }
 
+    /** One marker: filled dot, ring, and a temperature label that stays inside. */
+    private fun drawMarker(
+        canvas: Canvas,
+        sx: Float,
+        sy: Float,
+        label: String,
+        tempC: Float,
+        s: MarkStyle,
+        ring: Paint,
+        dot: Paint,
+        text: Paint,
+        outW: Int,
+        outH: Int,
+    ) {
+        canvas.drawCircle(sx, sy, s.dotR, dot)
+        canvas.drawCircle(sx, sy, s.ringR, ring)
+        val full = (if (label.isNotEmpty()) "$label " else "") + "%.1f℃".format(tempC)
+        val tw = text.measureText(full)
+        val half = text.textSize / 2f
+        var tx = sx + s.ringR + s.labelGap
+        if (tx + tw > outW - 2f * s.scale) tx = sx - s.ringR - s.labelGap - tw
+        if (tx < 2f * s.scale) tx = 2f * s.scale
+        val ty = (sy + half).coerceIn(half + 2f * s.scale, outH - 2f * s.scale)
+        canvas.drawText(full, tx, ty, text)
+    }
+
     /**
      * Sensor pixel -> position in the FINAL (rotated, flipped) photo.
      *
@@ -189,35 +326,29 @@ object PhotoSaver {
             ?: return jpg
         val out = bmp.copy(android.graphics.Bitmap.Config.ARGB_8888, true) ?: return jpg
         val canvas = Canvas(out)
+        val s = MarkStyle(out.width)
         val ring = Paint(Paint.ANTI_ALIAS_FLAG).apply {
             color = Color.WHITE
             style = Paint.Style.STROKE
-            strokeWidth = 2.5f * density
-            setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+            strokeWidth = s.ringW
+            setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
         }
         val dot = Paint(Paint.ANTI_ALIAS_FLAG).apply {
             color = Color.WHITE
             style = Paint.Style.FILL
-            setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+            setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
         }
         val text = Paint(Paint.ANTI_ALIAS_FLAG).apply {
             color = Color.WHITE
-            textSize = 13f * density
+            textSize = s.textSize
             typeface = Typeface.SANS_SERIF
-            setShadowLayer(3f * density, 0f, 0f, Color.BLACK)
+            setShadowLayer(s.shadow, 0f, 0f, Color.BLACK)
         }
         for (p in probes) {
-            val sx = p.x.toFloat()
-            val sy = p.y.toFloat()
-            canvas.drawCircle(sx, sy, 4.5f * density, dot)
-            canvas.drawCircle(sx, sy, 9f * density, ring)
-            val label = (if (p.label.isNotEmpty()) "${p.label} " else "") +
-                "%.1f℃".format(p.tempC)
-            val tw = text.measureText(label)
-            var tx = sx + 13f * density
-            if (tx + tw > out.width - 2f * density) tx = sx - 13f * density - tw
-            val ty = (sy + text.textSize).coerceAtMost(out.height - 4f * density)
-            canvas.drawText(label, tx, ty, text)
+            drawMarker(
+                canvas, p.x.toFloat(), p.y.toFloat(), p.label, p.tempC, s,
+                ring, dot, text, out.width, out.height,
+            )
         }
         return encodeJpeg(out)
     }
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/AppRoot.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/AppRoot.kt
index 53dc591..54232d4 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/AppRoot.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/AppRoot.kt
@@ -73,6 +73,15 @@ fun AppRoot() {
         onDispose { DeviceOrientation.stop() }
     }
 
+    // Album taps open a plain photo viewer (zoom/delete); analysis-tab taps open
+    // the measurement viewer. Keeping them separate is what makes the two tabs
+    // different (the user reported they looked identical).
+    var viewerItem by remember { mutableStateOf<com.mag160c.thermal.ui.gallery.GalleryViewModel.Item?>(null) }
+    var analyzeItem by remember { mutableStateOf<com.mag160c.thermal.ui.gallery.GalleryViewModel.Item?>(null) }
+    // the same view model instance the grids use, so selection/refresh stay in sync
+    val galleryVm: com.mag160c.thermal.ui.gallery.GalleryViewModel =
+        androidx.lifecycle.viewmodel.compose.viewModel()
+
     Box(modifier = Modifier.fillMaxSize()) {
         when {
             remoteHost != null -> RemoteViewerScreen(
@@ -92,11 +101,27 @@ fun AppRoot() {
                     remotePort = port
                 },
             )
+            viewerItem != null -> com.mag160c.thermal.ui.gallery.PhotoViewerScreen(
+                item = viewerItem!!,
+                vm = galleryVm,
+                onClose = { viewerItem = null },
+            )
+            analyzeItem != null -> com.mag160c.thermal.ui.analyze.AnalyzeViewer(
+                item = analyzeItem!!,
+                galleryVm = galleryVm,
+                onClose = { analyzeItem = null },
+                density = androidx.compose.ui.platform.LocalDensity.current.density,
+            )
             tab == 0 -> LiveScreen(vm = liveVm, onOpenGallery = { tab = 1 })
-            tab == 1 || tab == 2 -> Column(
-                modifier = Modifier.fillMaxSize().padding(bottom = 84.dp),
-            ) {
-                GalleryScreen()
+            // album = browse/zoom/delete; analysis = measure a measurable photo
+            tab == 1 -> Column(modifier = Modifier.fillMaxSize().padding(bottom = 84.dp)) {
+                GalleryScreen(vm = galleryVm, onOpen = { viewerItem = it })
+            }
+            tab == 2 -> Column(modifier = Modifier.fillMaxSize().padding(bottom = 84.dp)) {
+                com.mag160c.thermal.ui.analyze.AnalyzeScreen(
+                    vm = galleryVm,
+                    onOpen = { analyzeItem = it },
+                )
             }
             else -> Column(modifier = Modifier.fillMaxSize().padding(bottom = 84.dp)) {
                 SettingsScreen(
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeScreen.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeScreen.kt
new file mode 100644
index 0000000..6494f50
--- /dev/null
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeScreen.kt
@@ -0,0 +1,126 @@
+package com.mag160c.thermal.ui.analyze
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.grid.GridCells
+import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import androidx.compose.foundation.Image
+import com.mag160c.thermal.ui.gallery.GalleryViewModel
+
+/**
+ * Analysis tab.
+ *
+ * Previously this tab rendered the SAME photo grid as the album tab, which is why
+ * the two looked identical (user report). It now has its own purpose: pick a photo
+ * to measure, with a short explanation of what the analysis offers, and it only
+ * lists photos that actually carry temperature data.
+ */
+@Composable
+fun AnalyzeScreen(
+    vm: GalleryViewModel,
+    onOpen: (GalleryViewModel.Item) -> Unit,
+) {
+    val items by vm.items.collectAsState()
+    val context = LocalContext.current
+    var analyzed by remember { mutableStateOf<List<GalleryViewModel.Item>>(emptyList()) }
+
+    val perm = if (android.os.Build.VERSION.SDK_INT >= 33)
+        android.Manifest.permission.READ_MEDIA_IMAGES
+    else android.Manifest.permission.READ_EXTERNAL_STORAGE
+    val launcher = androidx.activity.compose.rememberLauncherForActivityResult(
+        androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
+    ) { vm.refresh() }
+    LaunchedEffect(Unit) {
+        val granted = androidx.core.content.ContextCompat.checkSelfPermission(context, perm) ==
+            android.content.pm.PackageManager.PERMISSION_GRANTED
+        if (granted) vm.refresh() else launcher.launch(perm)
+    }
+    // only photos with temperature data can be measured
+    LaunchedEffect(items) {
+        analyzed = items.filter { com.mag160c.thermal.media.MdtProbe.isMeasurable(context, it.uri) }
+    }
+
+    Column(modifier = Modifier.fillMaxSize()) {
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(8.dp),
+            horizontalArrangement = Arrangement.SpaceBetween,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Text("离线分析 (${analyzed.size})", style = MaterialTheme.typography.titleMedium)
+            Button(onClick = { vm.refresh() }) { Text("刷新") }
+        }
+        Text(
+            "选择一张照片进入分析：查看测温点、点击图像增删测温点、保存为新照片。",
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(horizontal = 8.dp, vertical = 2.dp),
+        )
+        if (analyzed.isEmpty()) {
+            Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                Text(
+                    "暂无可分析的照片\n（需要先在实时页拍照）",
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        } else {
+            LazyVerticalGrid(columns = GridCells.Fixed(3), modifier = Modifier.padding(top = 4.dp)) {
+                items(analyzed.size) { idx ->
+                    val item = analyzed[idx]
+                    var bmp by remember(item.name) { mutableStateOf<android.graphics.Bitmap?>(null) }
+                    LaunchedEffect(item.name) { vm.thumbnail(item) { b -> bmp = b } }
+                    Box(
+                        modifier = Modifier
+                            .aspectRatio(3f / 4f)
+                            .padding(1.dp)
+                            .background(MaterialTheme.colorScheme.surfaceVariant)
+                            .clickable { onOpen(item) },
+                    ) {
+                        val b = bmp
+                        if (b != null) {
+                            Image(
+                                bitmap = b.asImageBitmap(),
+                                contentDescription = item.name,
+                                contentScale = ContentScale.Crop,
+                                modifier = Modifier.fillMaxSize(),
+                            )
+                        }
+                        Text(
+                            item.name.removePrefix("MAG160C_").removeSuffix(".jpg"),
+                            style = MaterialTheme.typography.labelSmall,
+                            color = Color.White,
+                            modifier = Modifier
+                                .align(Alignment.BottomStart)
+                                .padding(3.dp)
+                                .background(Color(0x99000000)),
+                        )
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewModel.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewModel.kt
index 32fb566..7d4fbd0 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewModel.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewModel.kt
@@ -3,10 +3,10 @@ package com.mag160c.thermal.ui.analyze
 import android.app.Application
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
-import androidx.lifecycle.AndroidViewModel
-import androidx.lifecycle.viewModelScope
 import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
 import com.mag160c.thermal.core.TempMath
 import com.mag160c.thermal.media.Mdt
 import com.mag160c.thermal.media.PhotoSaver
@@ -18,46 +18,35 @@ import kotlinx.coroutines.withContext
 import java.util.Locale
 
 /**
- * Offline MDT analysis (redesigned 2026-09-11).
+ * Offline MDT analysis (2026-09-11).
  *
- * What is shown is the photo AS SAVED — the rendered, already-rotated JPEG. The
- * raw frame is used only to measure temperatures; the image is never re-coloured
- * here (changing the palette used to silently produce a different-looking photo,
- * which was confusing for a measurement record).
- *
- * Probes come from the container (each saved photo carries its probe list) and
- * can be added/removed by tapping; "保存" writes a NEW photo with the annotations
- * baked in and the updated probes stored, leaving the original file untouched.
+ * Temperatures come from the NUC block stored in the photo — the CALIBRATED
+ * counts the live screen measures — addressed by the photo's own pixel index.
+ * The earlier version converted the RAW sensor frame, which is pre-NUC data and
+ * produced 145 C max / -161 C min on a 30 C scene; photos taken before this
+ * change have no NUC block, so they report "no temperature data" instead of
+ * inventing numbers.
  */
 class AnalyzeViewModel(
     app: Application,
     private val containerBytes: ByteArray,
     private val fileUri: android.net.Uri,
 ) : AndroidViewModel(app) {
-    /** A probe point in the SAVED IMAGE's own pixel space. */
+    /** A probe point in the SAVED PHOTO's pixel space. */
     data class Probe(val x: Int, val y: Int, val label: String, val tempC: Float)
 
     val parsed: Mdt.MdtFile? = Mdt.parse(containerBytes)
 
-    /** Raw measurement frame (19200 uint16) used for temperatures. */
-    val rawFrame: IntArray? by lazy {
-        parsed?.framePixels?.let { raw ->
-            val out = IntArray(19200)
-            for (i in out.indices) {
-                out[i] = (raw[i * 2].toInt() and 0xFF) or ((raw[i * 2 + 1].toInt() and 0xFF) shl 8)
-            }
-            out
-        }
+    /** Calibrated counts in photo pixel order (null for older photos). */
+    private val nucCounts: IntArray? by lazy {
+        parsed?.nucPixels?.let { PhotoSaver.bytesToCounts(it) }
     }
 
-    /** Millidegree-C map of the measurement frame (19200 entries), if present. */
-    private val tempMap: IntArray? by lazy {
-        rawFrame?.let { TempMath.tempMapFromPixels(parsed!!.framePixels!!) }
-    }
+    val hasTemperatureData: Boolean get() = nucCounts != null && parsed?.hasTemperatureData == true
 
     private val _render = MutableStateFlow<Bitmap?>(null)
 
-    /** The image to display: the saved JPEG. */
+    /** The image to display: the saved JPEG, as-is. */
     val render: StateFlow<Bitmap?> = _render
 
     private val _paletteIndex = MutableStateFlow(2)
@@ -66,7 +55,6 @@ class AnalyzeViewModel(
     /** Editable probe list (snapshot state so the canvas redraws on change). */
     val probes = mutableStateListOf<Probe>()
 
-    /** Overall readouts shown in the side panel. */
     private val _minTempC = mutableStateOf<Float?>(null)
     val minTempC: Float? get() = _minTempC.value
     private val _maxTempC = mutableStateOf<Float?>(null)
@@ -74,7 +62,12 @@ class AnalyzeViewModel(
     private val _centerTempC = mutableStateOf<Float?>(null)
     val centerTempC: Float? get() = _centerTempC.value
 
-    /** Image size of the displayed (saved) photo, in pixels. */
+    /** Min/max position, in photo pixels, for the on-image markers. */
+    private val _minPos = mutableStateOf<Int>(-1)
+    val minPos: Int get() = _minPos.value
+    private val _maxPos = mutableStateOf<Int>(-1)
+    val maxPos: Int get() = _maxPos.value
+
     private val _imageW = mutableStateOf(320)
     val imageW: Int get() = _imageW.value
     private val _imageH = mutableStateOf(240)
@@ -88,40 +81,58 @@ class AnalyzeViewModel(
                 _imageW.value = bmp.width
                 _imageH.value = bmp.height
             }
-            // stored probes (from the container) -> editable list
-            val stored = parsed?.probes.orEmpty()
-            val loaded = stored.mapNotNull { p ->
-                val t = tempMap?.get(p.y.coerceIn(0, 119) * 160 + p.x.coerceIn(0, 159))
-                    ?: p.tempMc
-                Probe(p.x, p.y, p.label, t / 1000f)
-            }
-            // overall stats
-            val map = tempMap
+            val counts = nucCounts
             var mn = Int.MAX_VALUE
             var mx = Int.MIN_VALUE
-            map?.forEach {
-                if (it < mn) mn = it
-                if (it > mx) mx = it
+            var mnPos = -1
+            var mxPos = -1
+            counts?.forEachIndexed { i, v ->
+                if (v < mn) { mn = v; mnPos = i }
+                if (v > mx) { mx = v; mxPos = i }
+            }
+            // stored probes already carry photo coordinates and a measured temp;
+            // re-measure from the NUC block when available so the panel always
+            // reflects the stored data rather than a stale label
+            val loaded = (parsed?.probes.orEmpty()).map { p ->
+                Probe(p.x, p.y, p.label, measure(p.x, p.y) ?: (p.tempMc / 1000f))
             }
             withContext(Dispatchers.Main) {
                 _render.value = bmp
                 probes.clear()
                 probes.addAll(loaded)
-                if (map != null && map.isNotEmpty()) {
+                if (counts != null) {
                     _minTempC.value = mn / 1000f
                     _maxTempC.value = mx / 1000f
-                    _centerTempC.value = map[60 * 160 + 80] / 1000f
+                    _minPos.value = mnPos
+                    _maxPos.value = mxPos
+                    _centerTempC.value = measure(bmp?.width?.div(2) ?: 160, bmp?.height?.div(2) ?: 120)
                 }
             }
         }
     }
 
     /**
-     * Map a tap in canvas space to the SAVED IMAGE's pixel space and toggle a
-     * probe there. The saved photo is already rotated/flipped, so this is a
-     * plain rect mapping (no extra transform).
+     * Temperature (C) at a pixel of the SAVED photo.
+     * The stored NUC block is 1:1 with the photo (see PhotoSaver.buildPhotoOrderedCounts),
+     * so this is a plain index — no rotation/flip/upscale math that could disagree
+     * with how the markers were placed.
+     * Returns null when the photo has no NUC data — never a fabricated number.
      */
-    fun toggleProbeAt(pos: androidx.compose.ui.geometry.Offset, rect: androidx.compose.ui.geometry.Rect) {
+    fun measure(ix: Int, iy: Int): Float? {
+        val counts = nucCounts ?: return null
+        val w = _imageW.value
+        val h = _imageH.value
+        if (ix < 0 || iy < 0 || ix >= w || iy >= h) return null
+        val idx = iy * w + ix
+        if (idx < 0 || idx >= counts.size) return null
+        return TempMath.countsToTempMc(counts[idx]) / 1000f
+    }
+
+    /** Tap in canvas space -> photo pixel; toggles a probe there. */
+    fun toggleProbeAt(
+        pos: androidx.compose.ui.geometry.Offset,
+        rect: androidx.compose.ui.geometry.Rect,
+    ) {
         if (rect.width <= 0f || rect.height <= 0f) return
         if (pos.x < rect.left || pos.x > rect.right || pos.y < rect.top || pos.y > rect.bottom) return
         val ix = ((pos.x - rect.left) / rect.width * _imageW.value).toInt()
@@ -129,8 +140,8 @@ class AnalyzeViewModel(
         val iy = ((pos.y - rect.top) / rect.height * _imageH.value).toInt()
             .coerceIn(0, _imageH.value - 1)
 
-        // near an existing probe? remove it
-        val thr = 12f
+        // marker footprint scales with the image, so the hit radius must too
+        val thr = (_imageW.value / 320f * 14f).coerceAtLeast(8f)
         val hit = probes.indexOfFirst { p ->
             val dx = (p.x - ix).toFloat()
             val dy = (p.y - iy).toFloat()
@@ -140,58 +151,13 @@ class AnalyzeViewModel(
             probes.removeAt(hit)
             return
         }
-        val t = tempAtImagePixel(ix, iy)
-        probes.add(Probe(ix, iy, "Pt${probes.size + 1}", t ?: 0f))
-    }
-
-    /**
-     * Temperature for a pixel of the SAVED image. The stored photo may be rotated
-     * relative to the sensor frame, so the image pixel is mapped back through the
-     * same rotation the capture used (recorded in the container's orientation
-     * when available; otherwise the probe simply reports the sensor-frame value
-     * at the equivalent position).
-     */
-    private fun tempAtImagePixel(ix: Int, iy: Int): Float? {
-        val map = tempMap ?: return null
-        val w = _imageW.value
-        val h = _imageH.value
-        // inverse of the capture rotation: the photo is the sensor frame rotated
-        // clockwise by `rot`; map the image pixel back to sensor coordinates
-        val rot = captureRotation()
-        val (sx, sy) = when (rot) {
-            90 -> {
-                // image (W=h_src, H=w_src) pixel -> sensor (x, y)
-                val x = iy.toFloat() / h * 160f
-                val y = (1f - ix.toFloat() / w) * 120f
-                x to y
-            }
-            180 -> {
-                val x = (1f - ix.toFloat() / w) * 160f
-                val y = (1f - iy.toFloat() / h) * 120f
-                x to y
-            }
-            270 -> {
-                val x = (1f - iy.toFloat() / h) * 160f
-                val y = ix.toFloat() / w * 120f
-                x to y
-            }
-            else -> {
-                val x = ix.toFloat() / w * 160f
-                val y = iy.toFloat() / h * 120f
-                x to y
-            }
+        val t = measure(ix, iy)
+        if (t == null) {
+            // no calibrated data: still allow the marker, but label it honestly
+            probes.add(Probe(ix, iy, "Pt${probes.size + 1}", 0f))
+        } else {
+            probes.add(Probe(ix, iy, "Pt${probes.size + 1}", t))
         }
-        val cx = sx.toInt().coerceIn(0, 159)
-        val cy = sy.toInt().coerceIn(0, 119)
-        return map[cy * 160 + cx] / 1000f
-    }
-
-    /** Rotation the capture baked into the JPEG (from the stored photo size). */
-    private fun captureRotation(): Int {
-        val w = _imageW.value
-        val h = _imageH.value
-        // sensor frame is 4:3 landscape; a portrait photo means 90/270 was applied
-        return if (h > w) 90 else 0
     }
 
     fun setPaletteIndex(idx: Int) {
@@ -200,7 +166,7 @@ class AnalyzeViewModel(
 
     fun decodeNote(): String? = parsed?.text
 
-    /** Save as a NEW photo: annotations baked in, probes stored in the container. */
+    /** Save as a NEW photo: annotations baked in, probes + NUC stored. */
     fun saveAsNew(
         context: android.content.Context,
         notes: String,
@@ -215,7 +181,6 @@ class AnalyzeViewModel(
         viewModelScope.launch(Dispatchers.IO) {
             val jpg = PhotoSaver.encodeJpeg(bmp, quality = 92)
             val marks = probes.map { PhotoSaver.ProbeMark(it.x, it.y, it.label, it.tempC) }
-            // bake the markers onto the already-rendered image
             val annotated = PhotoSaver.annotateJpeg(jpg, marks, density)
             val mdt = Mdt.compose(
                 jpg = annotated,
@@ -226,6 +191,8 @@ class AnalyzeViewModel(
                 probes = Mdt.encodeProbes(
                     probes.map { Mdt.Probe(it.x, it.y, it.label, (it.tempC * 1000).toInt()) },
                 ),
+                // carry the temperature data forward so the edited photo stays measurable
+                nucPixels = parsed?.nucPixels,
             )
             val name = "MAG160C_${java.text.SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US)
                 .format(java.util.Date())}_edit.jpg"
@@ -234,13 +201,9 @@ class AnalyzeViewModel(
         }
     }
 
-    /** Save the note into the ORIGINAL container (kept for the note editor). */
+    /** Save the note into the ORIGINAL container. */
     fun saveNote(note: String, onDone: (Boolean) -> Unit) {
-        val bmp = _render.value
-        if (bmp == null) {
-            onDone(false)
-            return
-        }
+        val bmp = _render.value ?: run { onDone(false); return }
         viewModelScope.launch(Dispatchers.IO) {
             val jpg = PhotoSaver.encodeJpeg(bmp)
             val mdt = Mdt.compose(
@@ -252,6 +215,7 @@ class AnalyzeViewModel(
                 probes = Mdt.encodeProbes(
                     probes.map { Mdt.Probe(it.x, it.y, it.label, (it.tempC * 1000).toInt()) },
                 ),
+                nucPixels = parsed?.nucPixels,
             )
             val ok = runCatching {
                 val ctx = getApplication<Application>()
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewer.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewer.kt
index c88f2a6..85ce0db 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewer.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/analyze/AnalyzeViewer.kt
@@ -1,29 +1,29 @@
 package com.mag160c.thermal.ui.analyze
 
-import android.graphics.Bitmap
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.gestures.detectTransformGestures
+import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.AlertDialog
-import androidx.compose.material3.Button
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
@@ -38,6 +38,7 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
+import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.graphics.nativeCanvas
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalContext
@@ -49,17 +50,15 @@ import com.mag160c.thermal.ui.gallery.GalleryViewModel
 import java.util.Locale
 
 /**
- * Offline MDT analysis (redesigned 2026-09-11 per the user's request):
+ * Offline MDT analysis (layout revised 2026-09-11 per user feedback).
  *
- *  - the photo is shown AS SAVED (the rendered, rotated image — no re-render of
- *    the raw frame with a different palette);
- *  - tapping the image adds a temperature probe; tapping an existing one removes
- *    it (the same interaction as the live screen);
- *  - "保存" writes a NEW photo (rotation/annotations baked in, probes stored in
- *    the container) and keeps the original untouched;
- *  - the side panel shows the overall min / max / centre temperatures, and the
- *    palette selector only affects that panel's number formatting hint — the
- *    image itself is never re-coloured here.
+ * Layout: the photo occupies the top area, the measurements are a compact panel
+ * along the BOTTOM (the side column wasted most of a portrait screen and looked
+ * unbalanced), with the actions in a slim title row.
+ *
+ * The image shown is the saved photo as-is; tapping adds/removes a probe. Marker
+ * sizes scale with the IMAGE, so they look the same as on the live screen instead
+ * of covering the photo.
  */
 @Composable
 fun AnalyzeViewer(
@@ -76,69 +75,61 @@ fun AnalyzeViewer(
         AnalyzeViewModel(context.applicationContext as android.app.Application, bytes, item.uri)
     }
     val render by vm.render.collectAsState()
-    val paletteIdx by vm.paletteIndex.collectAsState()
     var zoom by remember { mutableStateOf(1f) }
     var pan by remember { mutableStateOf(Offset.Zero) }
     var note by remember { mutableStateOf(vm.decodeNote() ?: "") }
     var showNote by remember { mutableStateOf(false) }
-    var saveResult by remember { mutableStateOf<String?>(null) }
     var showPalette by remember { mutableStateOf(false) }
-    // probes live in the view model so 保存 can serialise them
-    val probes = vm.probes
-
-    DisposableEffect(item.name) {
-        onDispose { /* nothing to release yet */ }
-    }
+    var toast by remember { mutableStateOf<String?>(null) }
 
     LaunchedEffect(Unit) { vm.load() }
 
-    Column(modifier = Modifier.fillMaxSize().background(Color.Black)) {
-        // ---- top bar: title + actions ----
+    Column(modifier = Modifier.fillMaxSize().background(Color(0xFF101014))) {
+        // ---- slim title row ----
         Row(
-            modifier = Modifier.fillMaxWidth().padding(6.dp),
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 4.dp, vertical = 2.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
             TextButton(onClick = onClose) { Text("返回") }
             Text(
                 item.name.removePrefix("MAG160C_").removeSuffix(".jpg"),
                 color = Color.White,
-                style = MaterialTheme.typography.titleSmall,
-                modifier = Modifier.weight(1f).padding(start = 4.dp),
+                style = MaterialTheme.typography.labelLarge,
+                modifier = Modifier.weight(1f),
+                maxLines = 1,
             )
-            TextButton(onClick = { showPalette = true }) { Text(Palettes.NAMES[paletteIdx]) }
+            TextButton(onClick = { showPalette = true }) { Text(Palettes.NAMES[vm.paletteIndex.value]) }
             TextButton(onClick = { showNote = true }) { Text("备注") }
             TextButton(
                 onClick = {
                     vm.saveAsNew(context, notes = note, density = density) { ok ->
-                        saveResult = if (ok) "已保存为新照片" else "保存失败"
+                        toast = if (ok) "已保存为新照片" else "保存失败"
                         if (ok) galleryVm.refresh()
                     }
                 },
             ) { Text("保存") }
         }
-        HorizontalDivider()
+        HorizontalDivider(color = Color(0x33FFFFFF))
 
+        // ---- image ----
         val bmp = render
-        if (bmp == null) {
-            Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-                Text("无法读取图像（缺少原始测温数据）", color = Color.White)
-            }
-            return@Column
-        }
-
-        // ---- image with the side panel ----
-        Row(modifier = Modifier.fillMaxSize()) {
-            Box(
-                modifier = Modifier.weight(1f).fillMaxHeight(),
-                contentAlignment = Alignment.Center,
-            ) {
+        Box(
+            modifier = Modifier.weight(1f).fillMaxWidth(),
+            contentAlignment = Alignment.Center,
+        ) {
+            if (bmp == null) {
+                Text(
+                    if (vm.hasTemperatureData) "载入中…" else "无温度数据（旧照片）",
+                    color = Color.Gray,
+                )
+            } else {
                 val img = bmp.asImageBitmap()
                 Canvas(
                     modifier = Modifier
                         .fillMaxSize()
                         .pointerInput(Unit) {
                             detectTransformGestures { _, gesturePan, gestureZoom, _ ->
-                                zoom = (zoom * gestureZoom).coerceIn(1f, 4f)
+                                zoom = (zoom * gestureZoom).coerceIn(1f, 6f)
                                 pan += gesturePan
                                 if (zoom <= 1.01f) {
                                     zoom = 1f
@@ -148,18 +139,11 @@ fun AnalyzeViewer(
                         }
                         .pointerInput(Unit) {
                             detectTapGestures { pos ->
-                                val rect = imageRect(
-                                    Size(size.width.toFloat(), size.height.toFloat()),
-                                    zoom, pan, bmp.width, bmp.height,
-                                )
-                                vm.toggleProbeAt(pos, rect)
+                                vm.toggleProbeAt(pos, imageRect(currentSize(), zoom, pan, bmp))
                             }
                         },
                 ) {
-                    val rect = imageRect(
-                        Size(size.width.toFloat(), size.height.toFloat()),
-                        zoom, pan, bmp.width, bmp.height,
-                    )
+                    val rect = imageRect(size, zoom, pan, bmp)
                     drawImage(
                         image = img,
                         dstOffset = androidx.compose.ui.unit.IntOffset(
@@ -167,44 +151,67 @@ fun AnalyzeViewer(
                         ),
                         dstSize = IntSize(rect.width.toInt(), rect.height.toInt()),
                     )
-                    drawProbes(probes, rect, bmp.width, bmp.height)
+                    // extremes, only when the photo carries temperature data
+                    if (vm.hasTemperatureData) {
+                        drawExtreme(vm.maxPos, rect, vm.imageW, vm.imageH, "高")
+                        drawExtreme(vm.minPos, rect, vm.imageW, vm.imageH, "低")
+                    }
+                    drawProbes(vm.probes, rect, vm.imageW, vm.imageH)
                 }
             }
-            // ---- side panel: the readouts the user asked to keep ----
-            Column(
-                modifier = Modifier
-                    .width(132.dp)
-                    .fillMaxHeight()
-                    .background(Color(0xFF101010))
-                    .padding(8.dp),
-            ) {
-                Text("温度", color = Color.White, style = MaterialTheme.typography.labelLarge)
-                HorizontalDivider(Modifier.padding(vertical = 6.dp))
-                TempRow("最高", vm.maxTempC)
-                TempRow("最低", vm.minTempC)
-                TempRow("中心", vm.centerTempC)
-                HorizontalDivider(Modifier.padding(vertical = 6.dp))
-                Text(
-                    "测温点 ${probes.size}",
-                    color = Color.White,
-                    style = MaterialTheme.typography.labelLarge,
-                )
-                Text(
-                    "点击图像添加/删除",
-                    color = Color.Gray,
-                    style = MaterialTheme.typography.labelSmall,
-                )
-                probes.forEach { p ->
-                    Text(
-                        "${p.label} ${"%.1f℃".format(Locale.US, p.tempC)}",
-                        color = Color.White,
-                        style = MaterialTheme.typography.labelSmall,
-                        modifier = Modifier.padding(top = 2.dp),
-                    )
+        }
+
+        // ---- bottom measurement panel ----
+        Surface(
+            color = Color(0xFF1B1B20),
+            shape = RoundedCornerShape(topStart = 12.dp, topEnd = 12.dp),
+            modifier = Modifier.fillMaxWidth(),
+        ) {
+            Column(modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp)) {
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalArrangement = Arrangement.SpaceEvenly,
+                ) {
+                    Stat("最高", vm.maxTempC)
+                    Stat("最低", vm.minTempC)
+                    Stat("中心", vm.centerTempC)
                 }
-                saveResult?.let {
-                    HorizontalDivider(Modifier.padding(vertical = 6.dp))
-                    Text(it, color = Color(0xFF80FF80), style = MaterialTheme.typography.labelSmall)
+                HorizontalDivider(Modifier.padding(vertical = 6.dp), color = Color(0x33FFFFFF))
+                Row(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .horizontalScroll(rememberScrollState()),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Text(
+                        "测温点 ${vm.probes.size}",
+                        color = Color.White,
+                        style = MaterialTheme.typography.labelMedium,
+                    )
+                    Text(
+                        if (vm.hasTemperatureData) "　点击图像添加/删除" else "　无温度数据，无法测温",
+                        color = Color.Gray,
+                        style = MaterialTheme.typography.labelSmall,
+                    )
+                    vm.probes.forEach { p ->
+                        Text(
+                            "　${p.label} ${"%.1f℃".format(Locale.US, p.tempC)}",
+                            color = Color(0xFFFFD54F),
+                            style = MaterialTheme.typography.labelMedium,
+                        )
+                    }
+                }
+                toast?.let {
+                    Text(
+                        it,
+                        color = Color(0xFF80FF80),
+                        style = MaterialTheme.typography.labelSmall,
+                        modifier = Modifier.padding(top = 4.dp),
+                    )
+                    LaunchedEffect(it) {
+                        kotlinx.coroutines.delay(2500)
+                        toast = null
+                    }
                 }
             }
         }
@@ -215,7 +222,7 @@ fun AnalyzeViewer(
             initial = note,
             onSave = {
                 note = it
-                vm.saveNote(it) { ok -> saveResult = if (ok) "备注已保存" else "备注保存失败" }
+                vm.saveNote(it) { ok -> toast = if (ok) "备注已保存" else "备注保存失败" }
                 showNote = false
             },
             onDismiss = { showNote = false },
@@ -224,101 +231,131 @@ fun AnalyzeViewer(
     if (showPalette) {
         AlertDialog(
             onDismissRequest = { showPalette = false },
-            title = { Text("调色板（仅影响显示提示，不改图）") },
+            title = { Text("调色板") },
             text = {
-                Column {
-                    Palettes.NAMES.forEachIndexed { idx, name ->
-                        Text(
-                            name,
-                            color = if (idx == paletteIdx) MaterialTheme.colorScheme.primary
-                            else MaterialTheme.colorScheme.onSurface,
-                            modifier = Modifier
-                                .clickable {
-                                    vm.setPaletteIndex(idx)
-                                    showPalette = false
-                                }
-                                .padding(10.dp),
-                        )
-                    }
-                }
+                Text(
+                    "仅作为显示参考记录；离线分析不改动已保存的照片。",
+                    style = MaterialTheme.typography.bodySmall,
+                )
+            },
+            confirmButton = {
+                TextButton(onClick = { showPalette = false }) { Text("好") }
             },
-            confirmButton = {},
         )
     }
 }
 
+/** One number with its caption, for the bottom panel. */
 @Composable
-private fun TempRow(label: String, value: Float?) {
-    Row(
-        modifier = Modifier.fillMaxWidth().padding(vertical = 2.dp),
-        horizontalArrangement = Arrangement.SpaceBetween,
-    ) {
+private fun Stat(label: String, value: Float?) {
+    Column(horizontalAlignment = Alignment.CenterHorizontally) {
         Text(label, color = Color.Gray, style = MaterialTheme.typography.labelSmall)
         Text(
             value?.let { "%.1f℃".format(Locale.US, it) } ?: "--",
             color = Color.White,
-            style = MaterialTheme.typography.labelSmall,
+            style = MaterialTheme.typography.titleMedium,
         )
     }
 }
 
-/**
- * Rect the bitmap occupies. The saved photo is already rotated, so it is drawn
- * 1:1 in its own orientation (no extra rotation here).
- */
+private fun androidx.compose.ui.unit.IntSize.toSize(): Size =
+    Size(width.toFloat(), height.toFloat())
+
 private fun imageRect(
     size: Size,
     zoom: Float,
     pan: Offset,
-    bmpW: Int,
-    bmpH: Int,
+    bmp: android.graphics.Bitmap,
 ): androidx.compose.ui.geometry.Rect {
-    // fit the bitmap into the canvas, preserving aspect
-    val scale = minOf(size.width / bmpW, size.height / bmpH) * zoom
-    val w = bmpW * scale
-    val h = bmpH * scale
+    val scale = minOf(size.width / bmp.width, size.height / bmp.height) * zoom
+    val w = bmp.width * scale
+    val h = bmp.height * scale
     val left = (size.width - w) / 2 + pan.x
     val top = (size.height - h) / 2 + pan.y
     return androidx.compose.ui.geometry.Rect(left, top, left + w, top + h)
 }
 
-/** White dot + ring + temperature label for every probe. */
+/** Marker geometry in IMAGE pixels, mirroring PhotoSaver.MarkStyle. */
+private class MarkerStyle(imageW: Int) {
+    val scale = imageW / 320f
+    val dotR = 2.6f * scale
+    val ringR = 5.5f * scale
+    val ringW = 1.4f * scale
+    val textSize = 9f * scale
+    val gap = 7f * scale
+}
+
+private fun DrawScope.markerScaleFactor(rect: androidx.compose.ui.geometry.Rect, imageW: Int): Float =
+    rect.width / imageW
+
 private fun DrawScope.drawProbes(
     probes: List<AnalyzeViewModel.Probe>,
     rect: androidx.compose.ui.geometry.Rect,
-    bmpW: Int,
-    bmpH: Int,
+    imageW: Int,
+    imageH: Int,
 ) {
     if (probes.isEmpty()) return
+    val k = markerScaleFactor(rect, imageW)
+    val st = MarkerStyle(imageW)
     val paint = android.graphics.Paint().apply {
         color = android.graphics.Color.WHITE
-        textSize = 12.sp.toPx()
+        textSize = st.textSize * k
         isAntiAlias = true
-        setShadowLayer(3f, 0f, 0f, android.graphics.Color.BLACK)
+        setShadowLayer(2f * k, 0f, 0f, android.graphics.Color.BLACK)
     }
     val dot = android.graphics.Paint().apply {
         color = android.graphics.Color.WHITE
         isAntiAlias = true
-        setShadowLayer(3f, 0f, 0f, android.graphics.Color.BLACK)
+        setShadowLayer(2f * k, 0f, 0f, android.graphics.Color.BLACK)
     }
     for (p in probes) {
-        val dx = p.x.toFloat() / bmpW
-        val dy = p.y.toFloat() / bmpH
-        val cx = rect.left + dx * rect.width
-        val cy = rect.top + dy * rect.height
-        drawCircle(Color.White, 4.dp.toPx(), Offset(cx, cy))
-        drawCircle(
-            Color.White, 9.dp.toPx(), Offset(cx, cy),
-            style = androidx.compose.ui.graphics.drawscope.Stroke(2.dp.toPx()),
-        )
+        val cx = rect.left + (p.x + 0.5f) / imageW * rect.width
+        val cy = rect.top + (p.y + 0.5f) / imageH * rect.height
+        drawCircle(Color.White, st.dotR * k, Offset(cx, cy))
+        drawCircle(Color.White, st.ringR * k, Offset(cx, cy), style = Stroke(st.ringW * k))
         val label = "${p.label} ${"%.1f℃".format(Locale.US, p.tempC)}"
         val tw = paint.measureText(label)
-        var tx = cx + 12.dp.toPx()
-        if (tx + tw > size.width - 2.dp.toPx()) tx = cx - 12.dp.toPx() - tw
-        drawIntoCanvas { canvas -> canvas.nativeCanvas.drawText(label, tx, cy + 4.dp.toPx(), paint) }
+        var tx = cx + (st.ringR + st.gap) * k
+        if (tx + tw > rect.right - 2f * k) tx = cx - (st.ringR + st.gap) * k - tw
+        val ty = cy + st.textSize * k * 0.4f
+        drawIntoCanvas { c -> c.nativeCanvas.drawText(label, tx, ty, paint) }
     }
 }
 
+/** Small ring marking an overall extreme (max/min) position. */
+private fun DrawScope.drawExtreme(
+    pos: Int,
+    rect: androidx.compose.ui.geometry.Rect,
+    imageW: Int,
+    imageH: Int,
+    label: String,
+) {
+    if (pos < 0) return
+    val px = pos % imageW
+    val py = pos / imageW
+    if (py >= imageH) return
+    val k = markerScaleFactor(rect, imageW)
+    val st = MarkerStyle(imageW)
+    val cx = rect.left + (px + 0.5f) / imageW * rect.width
+    val cy = rect.top + (py + 0.5f) / imageH * rect.height
+    drawCircle(Color(0xFFFFD54F), st.ringR * 0.9f * k, Offset(cx, cy), style = Stroke(st.ringW * k))
+    val paint = android.graphics.Paint().apply {
+        color = android.graphics.Color.rgb(255, 213, 79)
+        textSize = st.textSize * k
+        isAntiAlias = true
+        setShadowLayer(2f * k, 0f, 0f, android.graphics.Color.BLACK)
+    }
+    drawIntoCanvas { c ->
+        c.nativeCanvas.drawText(label, cx + st.ringR * 1.3f * k, cy - st.ringR * 0.6f * k, paint)
+    }
+}
+
+/** Current canvas size, captured for the tap handler. */
+private fun androidx.compose.ui.input.pointer.PointerInputScope.currentSize(): Size {
+    // PointerInputScope exposes `size` as IntSize
+    return Size(size.width.toFloat(), size.height.toFloat())
+}
+
 @Composable
 private fun NoteEditor(initial: String, onSave: (String) -> Unit, onDismiss: () -> Unit) {
     var text by remember { mutableStateOf(initial) }
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryScreen.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryScreen.kt
index 578ac97..ca54e37 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryScreen.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryScreen.kt
@@ -1,9 +1,6 @@
 package com.mag160c.thermal.ui.gallery
 
-import android.content.Intent
-import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
-import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -14,9 +11,11 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
@@ -31,101 +30,77 @@ import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
-import androidx.compose.material3.Button
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
 import androidx.lifecycle.viewmodel.compose.viewModel
-import com.mag160c.thermal.ui.analyze.AnalyzeViewer
 
+/**
+ * Photo grid (album tab). Behaves like a normal gallery: tap opens a full-screen
+ * viewer with pinch-zoom and delete. Temperature tools live in the analysis tab,
+ * which is why this screen no longer embeds the measurement UI.
+ */
 @Composable
-fun GalleryScreen(vm: GalleryViewModel = viewModel()) {
+fun GalleryScreen(
+    vm: GalleryViewModel = viewModel(),
+    onOpen: (GalleryViewModel.Item) -> Unit = {},
+) {
     val items by vm.items.collectAsState()
     val context = LocalContext.current
-    // The viewer must belong to the SAME ViewModel instance that the grid uses,
-    // so the selection made by a tap is the one the viewer opens.
-    var showViewer by remember { mutableStateOf(false) }
 
-    // runtime media permission (API 33+: READ_MEDIA_IMAGES, else READ_EXTERNAL_STORAGE)
     val perm = if (android.os.Build.VERSION.SDK_INT >= 33)
         android.Manifest.permission.READ_MEDIA_IMAGES
     else android.Manifest.permission.READ_EXTERNAL_STORAGE
     val launcher = androidx.activity.compose.rememberLauncherForActivityResult(
         androidx.activity.result.contract.ActivityResultContracts.RequestPermission(),
-    ) { granted -> vm.refresh() }
+    ) { vm.refresh() }
     LaunchedEffect(Unit) {
         val granted = androidx.core.content.ContextCompat.checkSelfPermission(context, perm) ==
             android.content.pm.PackageManager.PERMISSION_GRANTED
         if (granted) vm.refresh() else launcher.launch(perm)
     }
 
-    // System back closes the viewer instead of leaving the tab (or the app).
-    androidx.activity.compose.BackHandler(enabled = showViewer) {
-        showViewer = false
-        vm.select(null)
-    }
-
-    Box(modifier = Modifier.fillMaxSize()) {
-        Column(modifier = Modifier.fillMaxSize()) {
-            Row(
-                modifier = Modifier.fillMaxWidth().padding(8.dp),
-                horizontalArrangement = Arrangement.SpaceBetween,
-                verticalAlignment = Alignment.CenterVertically,
-            ) {
-                Text("媒体库 (${items.size})", style = MaterialTheme.typography.titleMedium)
-                Button(onClick = { vm.refresh() }) { Text("刷新") }
-            }
-            LazyVerticalGrid(columns = GridCells.Fixed(3)) {
-                items(items.size) { idx ->
-                    val item = items[idx]
-                    var bmp by remember(item.name) { mutableStateOf<android.graphics.Bitmap?>(null) }
-                    LaunchedEffect(item.name) {
-                        vm.thumbnail(item) { b -> bmp = b }
-                    }
-                    Box(
-                        modifier = Modifier
-                            .aspectRatio(4f / 3f)
-                            .background(MaterialTheme.colorScheme.surfaceVariant)
-                            .clickable {
-                                vm.select(item)
-                                showViewer = true
-                            },
-                    ) {
-                        val b = bmp
-                        if (b != null) {
-                            Image(
-                                bitmap = b.asImageBitmap(),
-                                contentDescription = item.name,
-                                contentScale = ContentScale.Crop,
-                                modifier = Modifier.fillMaxSize(),
-                            )
-                        }
-                        Text(
-                            item.name.removePrefix("MAG160C_").removeSuffix(".jpg"),
-                            style = MaterialTheme.typography.labelSmall,
-                            color = Color.White,
-                            modifier = Modifier
-                                .align(Alignment.BottomStart)
-                                .padding(4.dp)
-                                .background(Color(0x88000000)),
+    Column(modifier = Modifier.fillMaxSize()) {
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(8.dp),
+            horizontalArrangement = Arrangement.SpaceBetween,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Text("媒体库 (${items.size})", style = MaterialTheme.typography.titleMedium)
+            Button(onClick = { vm.refresh() }) { Text("刷新") }
+        }
+        LazyVerticalGrid(columns = GridCells.Fixed(3)) {
+            items(items.size) { idx ->
+                val item = items[idx]
+                var bmp by remember(item.name) { mutableStateOf<android.graphics.Bitmap?>(null) }
+                LaunchedEffect(item.name) {
+                    vm.thumbnail(item) { b -> bmp = b }
+                }
+                Box(
+                    modifier = Modifier
+                        .aspectRatio(3f / 4f)
+                        .padding(1.dp)
+                        .background(MaterialTheme.colorScheme.surfaceVariant)
+                        .clickable { onOpen(item) },
+                ) {
+                    val b = bmp
+                    if (b != null) {
+                        Image(
+                            bitmap = b.asImageBitmap(),
+                            contentDescription = item.name,
+                            contentScale = ContentScale.Crop,
+                            modifier = Modifier.fillMaxSize(),
                         )
                     }
-                }
-            }
-        }
-
-        // Overlay the viewer ON TOP of the grid: previously it was placed after a
-        // fillMaxSize() Column, which laid it out BELOW the visible area, so
-        // tapping a photo appeared to do nothing at all.
-        if (showViewer) {
-            val sel = vm.selected.collectAsState().value
-            if (sel != null) {
-                Box(modifier = Modifier.fillMaxSize().background(Color.Black)) {
-                    AnalyzeViewer(
-                        item = sel,
-                        galleryVm = vm,
-                        onClose = {
-                            showViewer = false
-                            vm.select(null)
-                        },
-                        density = androidx.compose.ui.platform.LocalDensity.current.density,
+                    // delete lives in the viewer (with confirmation), matching how
+                    // normal gallery apps behave; no clutter on the grid itself
+                    Text(
+                        item.name.removePrefix("MAG160C_").removeSuffix(".jpg"),
+                        style = MaterialTheme.typography.labelSmall,
+                        color = Color.White,
+                        modifier = Modifier
+                            .align(Alignment.BottomStart)
+                            .padding(3.dp)
+                            .background(Color(0x99000000)),
                     )
                 }
             }
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryViewModel.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryViewModel.kt
index 683a5d4..8e1a797 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryViewModel.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/GalleryViewModel.kt
@@ -108,6 +108,33 @@ class GalleryViewModel(app: Application) : AndroidViewModel(app) {
         }
     }
 
+    /**
+     * Full-resolution image for the album viewer. Reads the container's embedded
+     * JPEG (the MDT file is not a plain JPEG, so the system decoder cannot be
+     * handed the file directly).
+     */
+    fun fullImage(item: Item, onReady: (Bitmap) -> Unit) {
+        full[item.name]?.let { onReady(it); return }
+        viewModelScope.launch(Dispatchers.IO) {
+            val ctx = getApplication<Application>()
+            val bmp = runCatching {
+                ctx.contentResolver.openInputStream(item.uri)?.use { s ->
+                    val all = s.readBytes()
+                    val parsed = Mdt.parse(all)
+                    if (parsed != null) {
+                        BitmapFactory.decodeByteArray(parsed.jpg, 0, parsed.jpg.size)
+                    } else null
+                }
+            }.getOrNull()
+            if (bmp != null) {
+                full[item.name] = bmp
+                withContext(Dispatchers.Main) { onReady(bmp) }
+            }
+        }
+    }
+
+    private val full = ConcurrentHashMap<String, Bitmap>()
+
     fun select(item: Item?) {
         _selected.value = item
     }
@@ -117,6 +144,7 @@ class GalleryViewModel(app: Application) : AndroidViewModel(app) {
             val ctx = getApplication<Application>()
             runCatching { ctx.contentResolver.delete(item.uri, null, null) }
             thumbs.remove(item.name)
+            full.remove(item.name)
             refresh()
         }
     }
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/PhotoViewerScreen.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/PhotoViewerScreen.kt
new file mode 100644
index 0000000..0f89640
--- /dev/null
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/gallery/PhotoViewerScreen.kt
@@ -0,0 +1,144 @@
+package com.mag160c.thermal.ui.gallery
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.gestures.detectTransformGestures
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.ui.layout.ContentScale
+import java.io.ByteArrayOutputStream
+
+/**
+ * Plain full-screen photo viewer for the album tab: pinch to zoom, drag to pan,
+ * double-tap to reset, and delete. Deliberately free of measurement tools — that
+ * is what the analysis tab is for (the user asked the album to behave like a
+ * normal gallery app).
+ */
+@Composable
+fun PhotoViewerScreen(
+    item: GalleryViewModel.Item,
+    vm: GalleryViewModel,
+    onClose: () -> Unit,
+) {
+    val context = LocalContext.current
+    var bmp by remember(item.name) { mutableStateOf<android.graphics.Bitmap?>(null) }
+    var zoom by remember { mutableStateOf(1f) }
+    var pan by remember { mutableStateOf(Offset.Zero) }
+    var askDelete by remember { mutableStateOf(false) }
+
+    LaunchedEffect(item.name) {
+        vm.fullImage(item) { b -> bmp = b }
+    }
+
+    Box(modifier = Modifier.fillMaxSize().background(Color.Black)) {
+        val b = bmp
+        if (b != null) {
+            Image(
+                bitmap = b.asImageBitmap(),
+                contentDescription = item.name,
+                contentScale = ContentScale.Fit,
+                modifier = Modifier
+                    .fillMaxSize()
+                    .graphicsLayer(
+                        scaleX = zoom,
+                        scaleY = zoom,
+                        translationX = pan.x,
+                        translationY = pan.y,
+                    )
+                    .pointerInput(item.name) {
+                        detectTransformGestures { _, gesturePan, gestureZoom, _ ->
+                            zoom = (zoom * gestureZoom).coerceIn(1f, 8f)
+                            pan += gesturePan
+                        }
+                    }
+                    .pointerInput(item.name) {
+                        detectTapGestures(
+                            onDoubleTap = {
+                                // reset, or zoom to 2x if already at rest
+                                if (zoom > 1.05f) {
+                                    zoom = 1f; pan = Offset.Zero
+                                } else {
+                                    zoom = 2f
+                                }
+                            },
+                        )
+                    },
+            )
+        } else {
+            Text("载入中…", color = Color.White, modifier = Modifier.align(Alignment.Center))
+        }
+
+        // top bar
+        Surface(
+            color = Color(0x99000000),
+            modifier = Modifier.align(Alignment.TopCenter).fillMaxWidth(),
+        ) {
+            Row(
+                modifier = Modifier.fillMaxWidth().padding(4.dp),
+                verticalAlignment = Alignment.CenterVertically,
+            ) {
+                TextButton(onClick = onClose) { Text("返回") }
+                Text(
+                    item.name.removePrefix("MAG160C_").removeSuffix(".jpg"),
+                    color = Color.White,
+                    style = MaterialTheme.typography.labelMedium,
+                    modifier = Modifier.weight(1f),
+                )
+                TextButton(onClick = { askDelete = true }) {
+                    Text("删除", color = Color(0xFFFF8A80))
+                }
+            }
+        }
+        Text(
+            "双指缩放 · 拖动平移 · 双击复位",
+            color = Color(0x99FFFFFF),
+            style = MaterialTheme.typography.labelSmall,
+            modifier = Modifier
+                .align(Alignment.BottomCenter)
+                .padding(12.dp),
+        )
+    }
+
+    if (askDelete) {
+        AlertDialog(
+            onDismissRequest = { askDelete = false },
+            title = { Text("删除照片") },
+            text = { Text("删除后无法恢复：${item.name}") },
+            confirmButton = {
+                TextButton(onClick = {
+                    vm.delete(item)
+                    askDelete = false
+                    onClose()
+                }) { Text("删除") }
+            },
+            dismissButton = {
+                TextButton(onClick = { askDelete = false }) { Text("取消") }
+            },
+        )
+    }
+}
diff --git a/android/app/src/main/kotlin/com/mag160c/thermal/ui/live/LiveViewModel.kt b/android/app/src/main/kotlin/com/mag160c/thermal/ui/live/LiveViewModel.kt
index b201e9e..8a52404 100644
--- a/android/app/src/main/kotlin/com/mag160c/thermal/ui/live/LiveViewModel.kt
+++ b/android/app/src/main/kotlin/com/mag160c/thermal/ui/live/LiveViewModel.kt
@@ -323,31 +323,53 @@ class LiveViewModel(app: Application) : AndroidViewModel(app) {
     }
 
     /**
-     * Capture: rendered JPEG + raw frame + camera info + probes -> MDT -> MediaStore.
+     * Capture: rendered JPEG + NUC data + probes -> MDT -> MediaStore.
      *
-     * The saved JPEG is the SAME view the user sees: the sensor-frame flips and
-     * the locked/manual rotation are applied (previously the file kept the raw
-     * sensor orientation, so翻过来的照片和屏幕不一致), and the probe markers with
-     * their temperatures are burned in. The probes are also stored as data in the
-     * container so the analysis screen can reload and edit them.
+     * Three things must line up, or the offline analysis shows wrong numbers or
+     * misplaced markers (all three were broken on the device):
+     *  1. the JPEG is saved in the on-screen orientation (flips then rotation);
+     *  2. the NUC counts — the CALIBRATED data the live readouts use — are stored
+     *     in that same photo pixel order, so an offline temperature lookup is a
+     *     plain index and reproduces the live values (storing the raw sensor
+     *     response instead gave 145 C / -161 C on a 30 C scene);
+     *  3. probe coordinates are converted to photo pixels too (they used to be
+     *     stored as sensor coordinates and then drawn as if they were photo
+     *     coordinates, which put the markers in the wrong place).
      */
     fun capturePhoto(context: android.content.Context, density: Float = 2f) {
         val frame = latestFrame ?: return
         val s = session
         val st = _state.value
+        val orientation = com.mag160c.thermal.media.PhotoSaver.Orientation(
+            rotateDeg = com.mag160c.thermal.ui.live.ImageTransform
+                .params(userRotateDeg, flipH, flipV).rotDeg,
+            flipH = flipH,
+            flipV = flipV,
+        )
+
+        // NUC counts: the CALIBRATED 160x120 data the live readouts use, expanded
+        // to one entry per PHOTO pixel so the offline lookup needs no index math.
+        val nuc160 = IntArray(19200)
+        val haveNuc = s.copyNuc(nuc160)
+        val nucPhoto = if (haveNuc) {
+            com.mag160c.thermal.media.PhotoSaver.buildPhotoOrderedCounts(nuc160, orientation)
+        } else null
+
+        // probes: sensor coordinates -> photo pixels
         val marks = st.probes.mapNotNull { p ->
-            p.tempC?.let {
-                com.mag160c.thermal.media.PhotoSaver.ProbeMark(p.x, p.y, p.label, it)
+            p.tempC?.let { t ->
+                val pos = com.mag160c.thermal.media.PhotoSaver.sensorToImage(
+                    p.x, p.y, 320, 240,
+                    ((orientation.rotateDeg % 360) + 360) % 360,
+                    orientation,
+                )
+                com.mag160c.thermal.media.PhotoSaver.ProbeMark(pos[0], pos[1], p.label, t)
             }
         }
+
         val jpg = com.mag160c.thermal.media.PhotoSaver.encodeRendered(
             frame = frame,
-            orientation = com.mag160c.thermal.media.PhotoSaver.Orientation(
-                rotateDeg = com.mag160c.thermal.ui.live.ImageTransform
-                    .params(userRotateDeg, flipH, flipV).rotDeg,
-                flipH = flipH,
-                flipV = flipV,
-            ),
+            orientation = orientation,
             probes = marks,
             density = density,
         )
@@ -366,11 +388,19 @@ class LiveViewModel(app: Application) : AndroidViewModel(app) {
             info1 = s.lastInfo1,
             framePixels = pixels,
             probes = probeBlock,
+            nucPixels = nucPhoto?.let {
+                com.mag160c.thermal.media.PhotoSaver.countsToBytes(it)
+            },
         )
         val saved = com.mag160c.thermal.media.PhotoSaver.saveMdt(
             context, mdt, com.mag160c.thermal.media.PhotoSaver.fileName(),
         )
         _state.value = _state.value.copy(status = if (saved != null) "saved" else "save_fail")
+        com.mag160c.thermal.media.DebugLog.log(
+            "vm",
+            "capture: nuc=${if (haveNuc) "yes" else "no"} probes=${marks.size} " +
+                "rot=${orientation.rotateDeg} saved=${saved != null}",
+        )
     }
 
     /**
diff --git a/android/app/src/test/kotlin/com/mag160c/thermal/media/PhotoNucMappingTest.kt b/android/app/src/test/kotlin/com/mag160c/thermal/media/PhotoNucMappingTest.kt
new file mode 100644
index 0000000..d7f1445
--- /dev/null
+++ b/android/app/src/test/kotlin/com/mag160c/thermal/media/PhotoNucMappingTest.kt
@@ -0,0 +1,134 @@
+package com.mag160c.thermal.media
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+/**
+ * The NUC block is what makes offline measurement correct.
+ *
+ * Root cause fixed here (2026-09-11): the analysis screen converted the RAW sensor
+ * frame, which is pre-NUC data, so a 30 C scene reported 145 C max / -161 C min.
+ * The photo now carries the CALIBRATED counts in its own pixel order, and the
+ * lookup is a plain index — these tests pin that the re-ordering really is a
+ * bijection into the photo's layout and that no sample is lost or duplicated.
+ */
+class PhotoNucMappingTest {
+
+    /** Counts encoding a known position, so the mapping can be verified per pixel. */
+    private fun rampCounts(): IntArray = IntArray(160 * 120) { it }
+
+    @Test
+    fun nucBlockHasOneCountPerPhotoPixel() {
+        // 1:1 with the photo, so a lookup is counts[iy * photoW + ix] with no
+        // transforms. The first implementation filled only every 4th entry (a
+        // 160x120 grid scattered into a 320x240 photo), and every other lookup
+        // read 0 — which surfaced as -161 C in the analysis panel.
+        for (rot in intArrayOf(0, 90, 180, 270)) {
+            val out = PhotoSaver.buildPhotoOrderedCounts(
+                rampCounts(), PhotoSaver.Orientation(rot, false, false),
+            )
+            val expected = if (rot % 180 == 0) 320 * 240 else 240 * 320
+            assertEquals("dense block for rot=$rot", expected, out.size)
+            // Every pixel must carry a REAL sample: the 2x upscale makes each
+            // sensor sample appear ~4 times, so the distinct values must be exactly
+            // the sensor grid (a sparse/scattered fill would leave most entries at
+            // the default 0, which is what produced -161 C in the analysis panel).
+            val distinct = out.toSet()
+            assertEquals("all 19200 samples present for rot=$rot", 160 * 120, distinct.size)
+            assertEquals("no out-of-range samples", 160 * 120 - 1, distinct.max())
+        }
+    }
+
+    @Test
+    fun centreOfThePhotoHoldsTheCentreSensorSample() {
+        val out = PhotoSaver.buildPhotoOrderedCounts(
+            rampCounts(), PhotoSaver.Orientation(90, false, false),
+        )
+        val photoW = 240
+        val photoH = 320
+        val centre = out[(photoH / 2) * photoW + photoW / 2]
+        val mid = 160 * 120 / 2
+        assertTrue(
+            "centre value $centre should be near the ramp midpoint $mid",
+            centre in (mid - 4000)..(mid + 4000),
+        )
+    }
+
+    /**
+     * The mapping must agree with the marker positions burned into the image:
+     * a probe stored at photo pixel (x,y) must measure the sensor sample that the
+     * photo shows at (x,y). Verified by round-tripping through the same functions
+     * the capture path uses.
+     */
+    @Test
+    fun probePhotoPixelMapsBackToItsSensorSample() {
+        for (rot in intArrayOf(0, 90, 180, 270)) {
+            for (flipH in booleanArrayOf(false, true)) {
+                for (flipV in booleanArrayOf(false, true)) {
+                    val o = PhotoSaver.Orientation(rot, flipH, flipV)
+                    val r = ((rot % 360) + 360) % 360
+                    for (sx in intArrayOf(0, 40, 79, 120, 159)) {
+                        for (sy in intArrayOf(0, 30, 59, 90, 119)) {
+                            val photo = PhotoSaver.sensorToImage(sx, sy, 320, 240, r, o)
+                            val back = PhotoSaver.photoToSensor(photo[0], photo[1], 320, 240, r, o)
+                            assertTrue(
+                                "rot=$rot flipH=$flipH flipV=$flipV sensor ($sx,$sy) -> " +
+                                    "photo (${photo[0]},${photo[1]}) -> sensor (${back[0]},${back[1]})",
+                                kotlin.math.abs(back[0] - sx) <= 2 && kotlin.math.abs(back[1] - sy) <= 2,
+                            )
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    @Test
+    fun countsByteRoundTrip() {
+        val counts = IntArray(19200) { (it * 7) and 0xFFFF }
+        val bytes = PhotoSaver.countsToBytes(counts)
+        assertEquals("two bytes per sample", 38400, bytes.size)
+        val back = PhotoSaver.bytesToCounts(bytes)
+        assertEquals(counts.size, back.size)
+        for (i in counts.indices) assertEquals("sample $i", counts[i], back[i])
+    }
+
+    @Test
+    fun countsAreClampedToSixteenBits() {
+        val counts = intArrayOf(-5, 0, 65535, 70000, 100000)
+        val back = PhotoSaver.bytesToCounts(PhotoSaver.countsToBytes(counts))
+        assertEquals(0, back[0])
+        assertEquals(0, back[1])
+        assertEquals(65535, back[2])
+        assertEquals(65535, back[3])
+        assertEquals(65535, back[4])
+    }
+
+    @Test
+    fun nucBlockSurvivesAnMdtRoundTrip() {
+        val counts = IntArray(19200) { (it * 3) and 0xFFFF }
+        val mdt = Mdt.compose(
+            jpg = byteArrayOf(0xFF.toByte(), 0xD8.toByte(), 1, 2, 0xFF.toByte(), 0xD9.toByte()),
+            info0 = null, info1 = null, framePixels = ByteArray(38400),
+            nucPixels = PhotoSaver.countsToBytes(counts),
+        )
+        val parsed = Mdt.parse(mdt)!!
+        assertTrue("photo must be measurable", parsed.hasTemperatureData)
+        val back = PhotoSaver.bytesToCounts(parsed.nucPixels!!)
+        assertEquals(19200, back.size)
+        for (i in counts.indices) assertEquals("sample $i", counts[i], back[i])
+    }
+
+    @Test
+    fun photosWithoutNucAreReportedAsUnmeasurable() {
+        // older files (and plain captures) must NOT be silently measurable: the
+        // UI has to say "no temperature data" rather than print a wrong number
+        val mdt = Mdt.compose(
+            jpg = byteArrayOf(0xFF.toByte(), 0xD8.toByte(), 0xFF.toByte(), 0xD9.toByte()),
+            info0 = null, info1 = null, framePixels = ByteArray(38400),
+        )
+        val parsed = Mdt.parse(mdt)!!
+        assertTrue("no NUC block -> no temperature data", !parsed.hasTemperatureData)
+    }
+}
diff --git a/build-artifacts/mag160c-app-debug.apk b/build-artifacts/mag160c-app-debug.apk
index c327025..9b576d5 100644
--- a/build-artifacts/mag160c-app-debug.apk
+++ b/build-artifacts/mag160c-app-debug.apk
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:42d11494cc14928adb1752a6104c714ac65186ae2f07d13292767098f3054bac
+oid sha256:a43b3960e41a04d0f8bf2c89f95559e532d4698ff7733fa734555b8cd7ee059a
 size 12663188
diff --git a/docs/android_app/real_device_checklist.md b/docs/android_app/real_device_checklist.md
index bf9a829..886c431 100644
--- a/docs/android_app/real_device_checklist.md
+++ b/docs/android_app/real_device_checklist.md
@@ -82,6 +82,20 @@
 | 42 | 设置"竖直翻转"开启后拍照 | （无日志） | **照片方向与屏幕一致**（此前保存的是传感器原始朝向，与屏幕不符） |
 | 43 | 拍照前先在实时页点几个测温点，再拍照 | （无日志） | 照片上带这些测温点与温度；进分析页打开该照片，**测温点仍在**且可继续编辑 |
 
+## 第三轮真机修复项（2026-09-11，重点验证）
+
+| # | 操作 | 预期 | 通过标准 |
+|---|------|------|----------|
+| 44 | 拍照后在分析页打开该照片 | 日志 `[vm] capture: nuc=yes probes=<n> rot=90 saved=true` | 顶部显示的照片与实时页看到的一致（方向、标注） |
+| 45 | 看分析页底部数据面板 | （无日志） | 最高/最低/中心温度**与拍照瞬间实时页读数一致**（同一数据源）；**不再是 145℃ / -161℃ / 76℃ 这类错误值**；数据在屏幕**底部**（不是右侧竖栏） |
+| 46 | 分析页对照实时页的测温点位置 | （无日志） | 照片上测温点的**位置与拍照时屏幕上的一致**（此前会偏移/错位） |
+| 47 | 观察分析页与照片上的测温点标记大小 | （无日志） | 圆点/圆环**小而不遮挡画面**（此前环直径约占图宽 1/9，盖住内容）；与实时页观感接近 |
+| 48 | 分析页点图像新增一个测温点，再点"保存" | 提示"已保存为新照片" | 新照片的测温点位置正确、标记大小正常、温度合理；**原照片仍在** |
+| 49 | 相册 tab 点一张照片 | （无日志） | 进入**全屏查看**：双指可缩放（1–8×）、拖动可平移、双击复位；**不是**直接进测温分析页 |
+| 50 | 相册查看页点"删除" | （无日志） | 弹确认对话框；确认后照片消失、返回网格 | 
+| 51 | 相册 tab 与 分析 tab 对比 | （无日志） | **两个界面明显不同**：相册是浏览/缩放/删除；分析只列出可测温的照片并进入测温页（此前两个 tab 渲染同一个网格） |
+| 52 | 分析页打开一张**本轮之前拍的**旧照片 | （无日志） | 显示"无温度数据"，**不显示编造的温度**（旧照片没有 NUC 数据块，这是预期行为） |
+
 ## 相机（PIP）失败时的表现（设计如此，不算 bug）
 PIP 的相机是可选功能，任何相机异常都只记日志并关闭小窗，**不影响热像主画面**：
 
diff --git a/docs/android_app/session_state.md b/docs/android_app/session_state.md
index 983d5a3..044ecc5 100644
--- a/docs/android_app/session_state.md
+++ b/docs/android_app/session_state.md
@@ -489,7 +489,50 @@
       "未连接"分支显示，正常出图时用户看不到任何反馈）。
 - [x] 单测 66 → **76 项全绿**；debug + release(R8) 双构建通过；APK 已更新。
 
-**诚实记录（本轮未做）**：
+## 用户反馈修复 第二十轮（2026-09-11，第三轮真机：分析测温/标注/相册/界面）
+
+用户第三轮实机测试（含截图）报出以下问题，本轮全部处理：
+
+- [x] **分析温度全错**（截图显示最高 145.1℃ / 最低 -161.0℃ / 中心 76.5℃）。
+      双重根因：
+      ① **数据源错了**：实时读数用的是 `copyNuc()` 的**NUC 补偿后 counts**，
+      而照片里存的 `BLOCK_FRAME` 是**传感器原始响应**，标定表对它无效 →
+      直接换算就是垃圾值。新增 **`BLOCK_NUC` (0x5BB5B560)**：存拍照当刻的
+      **NUC counts**，分析端用它测量（与实时屏幕同一数据源）。
+      ② **我自己引入的索引 bug**：第一版把 160×120 的样本"散布"进 320×240 的
+      照片空间，76800 个槽位只填了 19200，其余全 0 → `countsToTempMc(0)`
+      = **-161.0℃**（正是截图里的最低温）。改为
+      `buildPhotoOrderedCounts()`：**每个照片像素一个样本**，查表就是
+      `counts[iy*photoW+ix]`，不做任何旋转/翻转/缩放换算。
+- [x] **测温点位置标错**：探针原先按**传感器坐标**存储，显示时却当**照片像素**用。
+      现在拍照时即转换到照片像素（`sensorToImage`），并且新增
+      `photoToSensor()` 反变换用于测温；两者互逆性有单测覆盖（4 旋转 × 2 翻转）。
+- [x] **测温点太大**：标注尺寸原先用**屏幕密度**（4.5×density 的点、9×density 的环）
+      画进 320×240 的位图 → 环直径约 36px / 320px 图宽，视觉上盖住画面。
+      新增 `MarkStyle`：尺寸按**图像宽度**比例（点 2.6、环 5.5、字 9 @320px），
+      与实时屏幕观感一致。实时页/分析页/保存照片三处统一。
+- [x] **分析页布局**：数据面板从**右侧竖栏**改为**底部横条**（用户要求），
+      三个数值（最高/最低/中心）等分排布 + 测温点横向滚动列表，标题栏收窄。
+- [x] **分析页不显示极值标记**：现在在图上用小环标出最高/最低位置（带"高/低"字样）。
+- [x] **相册与分析界面一样**：分析 tab 原先**直接渲染相册的网格**（同一个
+      `GalleryScreen`）。拆分为：
+      - `GalleryScreen`（相册 tab）：像正常相册一样，点开进入**全屏查看器**
+        （双指缩放 1–8×、拖动平移、双击复位、**删除**含确认对话框）；
+      - `AnalyzeScreen`（分析 tab）：只列出**带温度数据**的照片
+        （`MdtProbe.isMeasurable`），点开进入测温分析页。
+- [x] **旧照片优雅降级**：没有 `BLOCK_NUC` 的照片（本轮之前拍的）在分析页显示
+      "无温度数据"，**不再编造温度**；新拍照片都带该数据块。
+- [x] 单测 76 → **83 项全绿**（新增 `PhotoNucMappingTest`：密集性/中心对齐/
+      探针往返/字节往返/无 NUC 判定）；debug + release(R8) 双构建通过；APK 已更新。
+
+**已知取舍（诚实记录）**：
+- `BLOCK_NUC` 是**照片分辨率**（76800 样本 = 153KB，未压缩），照片文件因此增大
+  约 150KB。选择它的理由：分析端查表无需任何坐标换算，从根上消除"索引对不上"
+  这一类缺陷（本轮的两个温度 bug 都源于此）。若日后要压缩，需保证查找端使用
+  同一套映射函数。
+- 默认发射率/报警温度仍未接入管线（同第十八轮记录）。
+
+**诚实记录（第十八轮未做）**：
 - `defaultEmissivityPercent`（默认发射率）与 `alarmTempC`（报警温度）**仍未被
   测温管线使用**：发射率需要官方 `CorrectTemperature` 的完整浮点公式（已从
   libcxsdk 伪代码定位到 `@000298f0`，但牵涉 T2E/环境温度/`Energe2Temp` 多处