diff --git a/frontools/screenshot.py b/frontools/screenshot.py
index d4350fd..6bb0c52 100644
--- a/frontools/screenshot.py
+++ b/frontools/screenshot.py
@@ -42,7 +42,7 @@ async def screenshot_diff(
         async with right_source.get_browser(
             width=width, height=height
         ) as right_browser:
-            urls = [(theme, url) for (theme, site) in config.sites for url in site.urls]
+            urls = [(site_name, url) for (site_name, site) in config.sites for url in site.urls]
 
             await report_progress(
                 "Screenshoting",
@@ -50,16 +50,16 @@ async def screenshot_diff(
                     (
                         url,
                         _diff_url(
-                            left_browser, right_browser, url, output_path / theme
+                            left_browser, right_browser, url, output_path, site_name
                         ),
                     )
-                    for (theme, url) in urls
+                    for (site_name, url) in urls
                 ],
                 nb_workers=3,
             )
 
 
-async def _diff_url(left: Browser, right: Browser, url: str, output_path: Path) -> None:
+async def _diff_url(left: Browser, right: Browser, url: str, output_path: Path, site_name: str) -> None:
     try:
         left_bytes = await _screenshot_url(left, url)
         right_bytes = await _screenshot_url(right, url)
@@ -81,10 +81,10 @@ async def _diff_url(left: Browser, right: Browser, url: str, output_path: Path)
         if not output_path.is_dir():
             output_path.mkdir()
 
-        with open(output_path / f"{url_slug}_left", "wb") as screenshot_file:
+        with open(output_path / f"{site_name}_{url_slug}_left", "wb") as screenshot_file:
             screenshot_file.write(left_bytes)
 
-        with open(output_path / f"{url_slug}_right", "wb") as screenshot_file:
+        with open(output_path / f"{site_name}_{url_slug}_right", "wb") as screenshot_file:
             screenshot_file.write(right_bytes)
     except Exception as ex:
         print(f"Error while diffing {url} : {ex}")