diff --git a/gateway/platforms/matrix.py b/gateway/platforms/matrix.py
index 77a2f240..dbdd8702 100644
--- a/gateway/platforms/matrix.py
+++ b/gateway/platforms/matrix.py
@@ -103,6 +103,23 @@ class MatrixAdapter(BasePlatformAdapter):
         self._dm_rooms: Dict[str, bool] = {}
         # Set of room IDs we've joined
         self._joined_rooms: Set[str] = set()
+        # Event deduplication (bounded deque keeps newest entries)
+        from collections import deque
+        self._processed_events: deque = deque(maxlen=1000)
+        self._processed_events_set: set = set()
+
+    def _is_duplicate_event(self, event_id) -> bool:
+        """Return True if this event was already processed. Tracks the ID otherwise."""
+        if not event_id:
+            return False
+        if event_id in self._processed_events_set:
+            return True
+        if len(self._processed_events) == self._processed_events.maxlen:
+            evicted = self._processed_events[0]
+            self._processed_events_set.discard(evicted)
+        self._processed_events.append(event_id)
+        self._processed_events_set.add(event_id)
+        return False
 
     # ------------------------------------------------------------------
     # Required overrides
@@ -188,7 +205,6 @@ class MatrixAdapter(BasePlatformAdapter):
 
         # Register event callbacks.
         client.add_event_callback(self._on_room_message, nio.RoomMessageText)
-        client.add_event_callback(self._on_room_message_media, nio.RoomMessageMedia)
         client.add_event_callback(self._on_room_message_media, nio.RoomMessageImage)
         client.add_event_callback(self._on_room_message_media, nio.RoomMessageAudio)
         client.add_event_callback(self._on_room_message_media, nio.RoomMessageVideo)
@@ -559,6 +575,10 @@ class MatrixAdapter(BasePlatformAdapter):
         if event.sender == self._user_id:
             return
 
+        # Deduplicate by event ID (nio can fire the same event more than once).
+        if self._is_duplicate_event(getattr(event, "event_id", None)):
+            return
+
         # Startup grace: ignore old messages from initial sync.
         event_ts = getattr(event, "server_timestamp", 0) / 1000.0
         if event_ts and event_ts < self._startup_ts - _STARTUP_GRACE_SECONDS:
@@ -648,6 +668,10 @@ class MatrixAdapter(BasePlatformAdapter):
         if event.sender == self._user_id:
             return
 
+        # Deduplicate by event ID.
+        if self._is_duplicate_event(getattr(event, "event_id", None)):
+            return
+
         # Startup grace.
         event_ts = getattr(event, "server_timestamp", 0) / 1000.0
         if event_ts and event_ts < self._startup_ts - _STARTUP_GRACE_SECONDS:
@@ -681,6 +705,24 @@ class MatrixAdapter(BasePlatformAdapter):
         elif event_mimetype:
             media_type = event_mimetype
 
+        # For images, download and cache locally so vision tools can access them.
+        # Matrix MXC URLs require authentication, so direct URL access fails.
+        cached_path = None
+        if msg_type == MessageType.PHOTO and url:
+            try:
+                ext_map = {
+                    "image/jpeg": ".jpg", "image/png": ".png",
+                    "image/gif": ".gif", "image/webp": ".webp",
+                }
+                ext = ext_map.get(event_mimetype, ".jpg")
+                download_resp = await self._client.download(url)
+                if isinstance(download_resp, nio.DownloadResponse):
+                    from gateway.platforms.base import cache_image_from_bytes
+                    cached_path = cache_image_from_bytes(download_resp.body, ext=ext)
+                    logger.info("[Matrix] Cached user image at %s", cached_path)
+            except Exception as e:
+                logger.warning("[Matrix] Failed to cache image: %s", e)
+
         is_dm = self._dm_rooms.get(room.room_id, False)
         if not is_dm and room.member_count == 2:
             is_dm = True
@@ -701,14 +743,18 @@ class MatrixAdapter(BasePlatformAdapter):
             thread_id=thread_id,
         )
 
+        # Use cached local path for images, HTTP URL for other media types
+        media_urls = [cached_path] if cached_path else ([http_url] if http_url else None)
+        media_types = [media_type] if media_urls else None
+
         msg_event = MessageEvent(
             text=body,
             message_type=msg_type,
             source=source,
             raw_message=getattr(event, "source", {}),
             message_id=event.event_id,
-            media_urls=[http_url] if http_url else None,
-            media_types=[media_type] if http_url else None,
+            media_urls=media_urls,
+            media_types=media_types,
         )
 
         await self.handle_message(msg_event)