Update app.py

app.py

@@ -135,7 +135,7 @@ def analyze_chart_with_openai(client, image_data, prompt, chart_type=None):
         ]
         
         response = client.chat.completions.create(
-            model="gpt-4",
+            model="gpt-4o",
             messages=messages,
             max_tokens=1000
         )