diff --git a/frontools/screenshot.py b/frontools/screenshot.py
index 430632d..7f2bada 100644
--- a/frontools/screenshot.py
+++ b/frontools/screenshot.py
@@ -65,8 +65,8 @@ async def _diff_url(
 ) -> None:
 
     url_slug = get_url_slug(url)
-    left_filename = output_path / f"{theme_name}_{url_slug}_left"
-    right_filename = output_path / f"{theme_name}_{url_slug}_right"
+    left_filename = output_path / f"{theme_name}_{url_slug}_left.png"
+    right_filename = output_path / f"{theme_name}_{url_slug}_right.png"
 
     if left_filename.is_file() and right_filename.is_file() and continue_:
         return