fix main with spinner

main.py

@@ -50,14 +50,22 @@ if st.button('Submit'):
     if bg_image:
         img_back=Image.open(bg_image).convert('RGB').resize(img_size)
         comp_img = img_back
-    if np.any(canvas_result.image_data):
+    elif np.any(canvas_result.image_data):
         img_draw=Image.fromarray(canvas_result.image_data).convert('RGB').resize(img_size)
         comp_img = img_draw
-    if bg_image and np.any(canvas_result.image_data):
+    elif bg_image and np.any(canvas_result.image_data):
+        img_back=Image.open(bg_image).convert('RGB').resize(img_size)
+        img_draw=Image.fromarray(canvas_result.image_data).convert('RGB').resize(img_size)
         comp_img = Image.new("RGB", img_size)
         comp_img = Image.blend(img_draw, img_back, alpha=0.5)
-
-    images = pipe_image(prompt=prompt,
+    else:
+        raise "Upload an image or draw something"
+    
+    if prompt is None:
+        raise "No prompt, no magic! :("
+        
+    with st.spinner('Wait for it...'):
+        images = pipe_image(prompt=prompt,
                        init_image=comp_img,
                        strength=strength)
     for image in images: