Update app.py

app.py

@@ -63,7 +63,7 @@ def navigate(screenshot, task: str, platform: str, history):
             "## Action Space\nclick(start_box='...') / type(...)\n\n"
             f"### Task\n{task}"
         )
-        user_history = [{"role":"user","content":prompt_header},{"role":"user","content":{"type": "image_url", "image_url": {"url": screenshot}}}]
+        user_history = [{"role":"user","content":prompt_header},{"role":"user","content":{"type": "image_url", "image_url":screenshot}}]
         messages = user_history