Upgrade the weights loading method to avoid duplicated loading.

app.py

@@ -54,7 +54,7 @@ birefnet.eval()
 def predict(image, resolution, weights_file):
  global birefnet
  # Load BiRefNet with chosen weights
- _weights_file = '/'.join(('zhengpeng7', usage_to_weights_file[weights_file] if weights_file is not None else 'BiRefNet'))
+ _weights_file = '/'.join(('zhengpeng7', usage_to_weights_file[weights_file] if weights_file is not None else usage_to_weights_file['General']))
  print('Change weights to:', _weights_file)
  birefnet = birefnet.from_pretrained(_weights_file)
  birefnet.to(device)