diff --git a/frontools/screenshot.py b/frontools/screenshot.py
index 439fb9a..161fd3e 100644
--- a/frontools/screenshot.py
+++ b/frontools/screenshot.py
@@ -67,14 +67,17 @@ async def _diff_url(left: Browser, right: Browser, url: str, output_path: Path)
 
         with NamedTemporaryFile(mode="wb") as left_file:
             left_file.write(left_bytes)
-            left_image = Image.open(left_file.name)
+            left_image = Image.open(left_file.name).convert('RGB')
 
         with NamedTemporaryFile(mode="wb") as right_file:
             right_file.write(right_bytes)
-            right_image = Image.open(right_file.name)
+            right_image = Image.open(right_file.name).convert('RGB')
 
         diff = ImageChops.difference(left_image, right_image)
 
+        if not diff.getbbox():
+            return
+
         url_slug = get_url_slug(url)
         if not output_path.is_dir():
             output_path.mkdir()