fix: Ensure input image is converted to RGB format in process_sr function

app.py

@@ -328,6 +328,9 @@ def process_sr(
         transforms.Resize(process_size, interpolation=transforms.InterpolationMode.BILINEAR),
     ])
 
+    if input_image.mode != 'RGB':
+        input_image = input_image.convert('RGB')
+
     seed_everything(seed)
     generator = torch.Generator(device=dit4sr_device)
     generator.manual_seed(seed)