update examples

app.py

@@ -51,7 +51,7 @@ class App:
 
                     with gr.Column():
                         examples = [
-                            [os.path.join("examples", "dance.mp4"), os.path.join("examples", "ref.jpg"),
+                            [os.path.join("examples", "dance.mp4"), os.path.join("examples", "ref.png"),
                              512, 720, 0, 300]]
                         ex_step1 = gr.Examples(examples=examples,
                                                inputs=[vid_dance_input, img_pose_input, nb_detect_resolution,