Update app.py

app.py

@@ -90,7 +90,10 @@ elif upload_option == "Webcam":
 
     if run_webcam:
         camera = cv2.VideoCapture(0)
-        st.session_state['run'] = True
+        if not camera.isOpened():
+            st.error("Could not open webcam. Please check if it is connected and try again.")
+        else:
+            st.session_state['run'] = True
 
     if 'run' in st.session_state and st.session_state['run']:
         while True: