Performance check
Image format
Finds <img> files in JPEG, PNG, GIF, BMP or TIFF (by file extension or data URI) that don’t sit in a <picture> with a WebP or AVIF source.
- Category
- Performance
- Importance
- Medium importance
- Check id
- image-format
How the result is decided
- PassNo images in older formats.
- WarningAt least one image uses an older format without a modern alternative.
- InfoThe page has no images.
“Info” results don’t count toward the score.
Why it matters
WebP and AVIF are typically 25–50% smaller than JPEG or PNG at the same quality, which saves bandwidth and speeds up the page.
How to fix it
Convert the images, or serve modern formats with a fallback. Many CDNs and image services convert automatically.
<picture>
<source srcset="/hero.avif" type="image/avif">
<source srcset="/hero.webp" type="image/webp">
<img src="/hero.jpg" alt="…">
</picture>After the fix, open the page’s report and choose Run again to confirm it passes.