diff --git a/app/session/[id].tsx b/app/session/[id].tsx
index 553c3e9..a538595 100644
--- a/app/session/[id].tsx
+++ b/app/session/[id].tsx
@@ -145,6 +145,14 @@ export default function SessionScreen() {
     }, []),
   )
 
+  // Surface speech recognition failures (e.g. mic permission denied). Keyed
+  // on the error value itself so it only fires once per distinct error, not
+  // on every re-render while it remains set.
+  useEffect(() => {
+    if (!speech.error) return
+    Alert.alert(t("session.alerts.speechErrorTitle"), t("session.alerts.speechErrorMessage"))
+  }, [speech.error, t])
+
   // Slash command state
   const slashActive = input.startsWith("/") && !input.includes(" ")
   const slashQuery = slashActive ? input.slice(1) : ""
@@ -335,12 +343,21 @@ export default function SessionScreen() {
     const result = await ImagePicker.launchImageLibraryAsync({
       mediaTypes: ["images"],
       allowsMultipleSelection: true,
+      selectionLimit: 10,
       quality: 1, // full quality - we compress in manipulator
     })
     if (result.canceled) return
-    const items = await Promise.all(result.assets.map((a) => toJpeg(a.uri, a.width, a.height)))
-    setAttachments((prev) => [...prev, ...items])
-  }, [])
+    const settled = await Promise.allSettled(result.assets.map((a) => toJpeg(a.uri, a.width, a.height)))
+    const items = settled.filter((r) => r.status === "fulfilled").map((r) => r.value)
+    if (items.length) setAttachments((prev) => [...prev, ...items])
+    if (settled.some((r) => r.status === "rejected")) {
+      console.error(
+        "Failed to process image(s):",
+        settled.filter((r) => r.status === "rejected").map((r) => r.reason),
+      )
+      Alert.alert(t("session.alerts.imageFailedTitle"), t("session.alerts.imageFailedMessage"))
+    }
+  }, [t])
 
   const pickFromCamera = useCallback(async () => {
     const perm = await ImagePicker.requestCameraPermissionsAsync()
@@ -351,8 +368,13 @@ export default function SessionScreen() {
     const result = await ImagePicker.launchCameraAsync({ quality: 1 })
     if (result.canceled) return
     const a = result.assets[0]
-    const item = await toJpeg(a.uri, a.width, a.height)
-    setAttachments((prev) => [...prev, item])
+    try {
+      const item = await toJpeg(a.uri, a.width, a.height)
+      setAttachments((prev) => [...prev, item])
+    } catch (err) {
+      console.error("Failed to process photo:", err)
+      Alert.alert(t("session.alerts.imageFailedTitle"), t("session.alerts.imageFailedMessage"))
+    }
   }, [t])
 
   const pasteFromClipboard = useCallback(async () => {
@@ -362,16 +384,8 @@ export default function SessionScreen() {
       const img = await Clipboard.getImageAsync({ format: "png" })
       if (img?.data) {
         const uri = img.data.startsWith("data:") ? img.data : `data:image/png;base64,${img.data}`
-        setAttachments((prev) => [
-          ...prev,
-          {
-            uri,
-            mime: "image/png",
-            filename: "clipboard.png",
-            width: img.size.width,
-            height: img.size.height,
-          },
-        ])
+        const item = await toJpeg(uri, img.size.width, img.size.height)
+        setAttachments((prev) => [...prev, item])
         return
       }
     }
@@ -617,7 +631,17 @@ export default function SessionScreen() {
         {revertMessageID && (
           <View style={[s.banner, s.bannerRevert]}>
             <Text style={s.bannerText}>{t("session.banners.reverted")}</Text>
-            <TouchableOpacity onPress={() => unrevertSession()} hitSlop={8}>
+            <TouchableOpacity
+              onPress={() => {
+                unrevertSession()
+                // The composer was prefilled with the reverted message's text/
+                // attachments (see applyRevertResult) — clear it so Undo doesn't
+                // leave a stale draft that could be sent as a duplicate.
+                setInput("")
+                setAttachments([])
+              }}
+              hitSlop={8}
+            >
               <Text style={s.bannerAction}>{t("session.banners.undo")}</Text>
             </TouchableOpacity>
           </View>
diff --git a/src/lib/i18n/en.json b/src/lib/i18n/en.json
index 8981093..a6e951f 100644
--- a/src/lib/i18n/en.json
+++ b/src/lib/i18n/en.json
@@ -118,7 +118,11 @@
       "replyFailedTitle": "Reply Failed",
       "replyFailedMessage": "Could not send your response. Please try again.",
       "rejectFailedTitle": "Reject Failed",
-      "rejectFailedMessage": "Could not send your response. Please try again."
+      "rejectFailedMessage": "Could not send your response. Please try again.",
+      "imageFailedTitle": "Image not attached",
+      "imageFailedMessage": "One or more images could not be processed. Please try a different photo.",
+      "speechErrorTitle": "Voice input failed",
+      "speechErrorMessage": "Could not use voice input. Check your microphone permission and try again."
     }
   },
   "connection": {
diff --git a/src/lib/i18n/zh-Hans.json b/src/lib/i18n/zh-Hans.json
index 447aa4e..f7a36a9 100644
--- a/src/lib/i18n/zh-Hans.json
+++ b/src/lib/i18n/zh-Hans.json
@@ -118,7 +118,11 @@
       "replyFailedTitle": "回复失败",
       "replyFailedMessage": "无法发送您的回复。请重试。",
       "rejectFailedTitle": "拒绝失败",
-      "rejectFailedMessage": "无法发送您的回复。请重试。"
+      "rejectFailedMessage": "无法发送您的回复。请重试。",
+      "imageFailedTitle": "图片未添加",
+      "imageFailedMessage": "一张或多张图片无法处理。请尝试其他照片。",
+      "speechErrorTitle": "语音输入失败",
+      "speechErrorMessage": "无法使用语音输入。请检查麦克风权限后重试。"
     }
   },
   "connection": {
diff --git a/src/lib/speech.ts b/src/lib/speech.ts
index d73519b..597fccf 100644
--- a/src/lib/speech.ts
+++ b/src/lib/speech.ts
@@ -1,4 +1,4 @@
-import { useState, useCallback, useRef } from "react"
+import { useState, useCallback, useRef, useEffect } from "react"
 import { ExpoSpeechRecognitionModule, useSpeechRecognitionEvent } from "expo-speech-recognition"
 
 interface SpeechState {
@@ -76,5 +76,13 @@ export function useSpeech(onResult: (text: string) => void): SpeechState & Speec
     setTranscript("")
   }, [])
 
+  // Stop the native recognition session when the screen unmounts — otherwise
+  // the mic stays hot in the background. abort() is a no-op when not listening.
+  useEffect(() => {
+    return () => {
+      ExpoSpeechRecognitionModule.abort()
+    }
+  }, [])
+
   return { listening, transcript, error, start, stop, cancel }
 }
diff --git a/src/stores/sessions.ts b/src/stores/sessions.ts
index 196c589..db22834 100644
--- a/src/stores/sessions.ts
+++ b/src/stores/sessions.ts
@@ -306,20 +306,10 @@ export const useSessions = create<SessionsState>((set, get) => ({
         }
       }
 
-      // Fire and forget - SSE events will update messages/parts/status in real-time
-      client.session.prompt(session.id, { parts: promptParts, model, agent, variant }).catch((err) => {
-        console.error("Failed to send message:", err)
-        // The user may have switched sessions while this send was in flight. Clear
-        // the sending flag for the session we actually sent to (keyed by id, safe),
-        // but only surface the error / refresh messages if it's still on screen —
-        // otherwise we'd flash an error on, and refetch, the wrong session.
-        const stillCurrent = get().currentSession?.id === session.id
-        set((state) => ({
-          ...(stillCurrent ? { error: String(err) } : {}),
-          sending: { ...state.sending, [session.id]: false },
-        }))
-        if (stillCurrent) get().refreshMessages()
-      })
+      // Await submission (POST to /prompt_async resolves fast, well before the
+      // streamed response) so a failure here can propagate to the caller — SSE
+      // events still update messages/parts/status in real-time on success.
+      await client.session.prompt(session.id, { parts: promptParts, model, agent, variant })
     } catch (err) {
       console.error("[sendMessage] error:", err)
       const stillCurrent = get().currentSession?.id === session.id
@@ -328,6 +318,7 @@ export const useSessions = create<SessionsState>((set, get) => ({
         sending: { ...state.sending, [session.id]: false },
       }))
       if (stillCurrent) get().refreshMessages()
+      throw err
     }
   },