diff --git a/src/components/nodes/VideoStitchNode.tsx b/src/components/nodes/VideoStitchNode.tsx
index accee880..c39a86d0 100644
--- a/src/components/nodes/VideoStitchNode.tsx
+++ b/src/components/nodes/VideoStitchNode.tsx
@@ -131,44 +131,66 @@ export function VideoStitchNode({ id, data, selected }: NodeProps<VideoStitchNod
 
   // Ref-based cache so the effect doesn't read stale `thumbnails` state
   const thumbnailsRef = useRef<Map<string, string>>(new Map());
+  // Fingerprint cache: edgeId -> last-20-chars of videoData, used to detect which clips changed
+  const thumbnailFingerprintsRef = useRef<Map<string, string>>(new Map());
 
   // Extract thumbnails from connected videos
   useEffect(() => {
     let cancelled = false;
 
+    const cleanupVideo = (video: HTMLVideoElement) => {
+      video.onloadedmetadata = null;
+      video.onerror = null;
+      video.onseeked = null;
+      video.src = "";
+      video.load();
+    };
+
     const extractThumbnails = async () => {
-      thumbnailsRef.current = new Map();
       const newThumbnails = new Map<string, string>();
+      const newFingerprints = new Map<string, string>();
 
       for (const clip of orderedClips) {
         if (cancelled) return;
         if (!clip.videoData) continue;
-        if (thumbnailsRef.current.has(clip.edgeId)) {
+
+        const fingerprint = clip.videoData.slice(-20);
+        newFingerprints.set(clip.edgeId, fingerprint);
+
+        // Reuse cached thumbnail if the video data hasn't changed
+        const cachedFingerprint = thumbnailFingerprintsRef.current.get(clip.edgeId);
+        if (cachedFingerprint === fingerprint && thumbnailsRef.current.has(clip.edgeId)) {
           newThumbnails.set(clip.edgeId, thumbnailsRef.current.get(clip.edgeId)!);
           continue;
         }
 
+        const video = document.createElement("video");
         try {
-          const video = document.createElement("video");
           video.src = clip.videoData;
           video.crossOrigin = "anonymous";
           video.muted = true;
+          video.preload = "metadata";
 
           await new Promise<void>((resolve, reject) => {
             video.onloadedmetadata = () => resolve();
             video.onerror = () => reject(new Error("Failed to load video"));
           });
 
-          if (cancelled) return;
+          if (cancelled) { cleanupVideo(video); return; }
 
           const seekTime = video.duration * 0.25;
           video.currentTime = seekTime;
 
-          await new Promise<void>((resolve) => {
-            video.onseeked = () => resolve();
-          });
+          await Promise.race([
+            new Promise<void>((resolve) => {
+              video.onseeked = () => resolve();
+            }),
+            new Promise<void>((_, reject) =>
+              setTimeout(() => reject(new Error("Seek timeout")), 10_000)
+            ),
+          ]);
 
-          if (cancelled) return;
+          if (cancelled) { cleanupVideo(video); return; }
 
           const canvas = document.createElement("canvas");
           const thumbWidth = 160;
@@ -177,7 +199,7 @@ export function VideoStitchNode({ id, data, selected }: NodeProps<VideoStitchNod
           canvas.width = thumbWidth;
           canvas.height = Math.round(thumbWidth / aspectRatio);
           const ctx = canvas.getContext("2d");
-          if (!ctx) continue;
+          if (!ctx) { cleanupVideo(video); continue; }
 
           ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
           const thumbnail = canvas.toDataURL("image/jpeg", 0.7);
@@ -187,10 +209,12 @@ export function VideoStitchNode({ id, data, selected }: NodeProps<VideoStitchNod
         } catch (error) {
           console.warn(`Failed to extract thumbnail for clip ${clip.edgeId}:`, error);
         }
+        cleanupVideo(video);
       }
 
       if (!cancelled) {
         thumbnailsRef.current = newThumbnails;
+        thumbnailFingerprintsRef.current = newFingerprints;
         setThumbnails(newThumbnails);
       }
     };