bug fix

app.py

@@ -18,6 +18,7 @@ from diffusers import DiffusionPipeline
 model = None
 ddim_scheduler = None
 model_type = None
+curr_model_name = None
 
 def load_image(image_path):
     """Process input image to tensor format."""
@@ -40,11 +41,13 @@ def process_image(image_choice, noise_sigma, operator_key, T, K):
     device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
     
     # Initialize model inside GPU-decorated function
-    global model, ddim_scheduler, model_type
-    if model is None:
+    global model, curr_model_name, ddim_scheduler, model_type
+    model_name = "google/ddpm-celebahq-256" if "Celeb" in image_choice else "google/ddpm-church-256"
+
+    if model is None or curr_model_name != model_name:
         model_type = "diffusers"
-        model_name = "google/ddpm-celebahq-256" if "Celeb" in image_choice else "google/ddpm-church-256"
         model = DiffusionPipeline.from_pretrained(model_name).to(device).unet
+        curr_model_name = model_name
         ddim_scheduler = DDIMScheduler(
             num_train_timesteps=1000,
             beta_start=0.0001,