update preprocess_image to handle numpy arrays and improve image conversion

app.py

@@ -62,11 +62,16 @@ def end_session(req: gr.Request):
     user_dir = os.path.join(TMP_DIR, str(req.session_hash))
     shutil.rmtree(user_dir)
 
-def preprocess_image(image: Image.Image) -> Image.Image:
+def preprocess_image(image):
     trellis = get_trellis_pipeline()
     if trellis is None:
         # If the pipeline is not loaded, just return the original image
         return image
+    
+    # Check if image is a numpy array and convert to PIL Image if needed
+    if isinstance(image, np.ndarray):
+        image = Image.fromarray(image.astype('uint8'))
+        
     # trellis.cuda()
     processed_image = trellis.preprocess_image(image)
     return processed_image