Change the default model choice for bb and Mi Sheng.

app.py

@@ -257,9 +257,11 @@ examples = [[_] for _ in glob('examples/*')][:]
 for idx_example, example in enumerate(examples):
     if 'My_' in example[0]:
         example_resolution = '2048x2048'
+        model_choice = 'Matting-HR'
     else:
         example_resolution = '1024x1024'
-    examples[idx_example] = examples[idx_example] + [example_resolution, 'General']
+        model_choice = 'General'
+    examples[idx_example] = examples[idx_example] + [example_resolution, ]
 
 examples_url = [
     ['https://hips.hearstapps.com/hmg-prod/images/gettyimages-1229892983-square.jpg'],