Update app.py

app.py

@@ -101,7 +101,7 @@ class WaifuDiffusionInterrogator:
     def interrogate(self, image: Image) -> Tuple[Dict[str, float], Dict[str, float]]:
         
         imgByteArr = io.BytesIO()
-        image.save(imgByteArr, format=image.format)
+        image.save(imgByteArr, format="png")
         imgByteArr = imgByteArr.getvalue()
         if imgByteArr in cache:
             return cache[imgByteArr]