Update app.py

app.py

@@ -190,7 +190,7 @@ async def v1_images_generations(request: Request, authorization: str = Header(No
     # These are there only to satisfy OpenAI-compatible clients
     _model = payload.get("model", "dall-e-3")  # ignored
     n = int(payload.get("n", 1))
-    response_format = payload.get("response_format", "url")  # "url" | "b64_json"
+    response_format = payload.get("response_format", "b64_json")  # "url" | "b64_json"
     size = payload.get("size", "1024x1024")
     quality = payload.get("quality")
     style = payload.get("style")