Update app.py

app.py

@@ -2234,8 +2234,15 @@ def similarity_matching(sprites_data: str, project_folder: str) -> str:
     # then backdrop as the Stage
     if backdrop_data:
         all_costumes, sounds = [], []
+        seen_costumes = set()
         for i, bd in enumerate(backdrop_data):
-            all_costumes.extend(bd.get("costumes", []))
+            for costume in bd.get("costumes", []):
+                # Create a unique key for the costume
+                key = (costume.get("name"), costume.get("assetId"))
+                if key not in seen_costumes:
+                    seen_costumes.add(key)
+                    all_costumes.append(costume)
+    
             if i == 0:
                 sounds = bd.get("sounds", [])
         stage_obj={