Images could use WebP or AVIF

Medium priorityImages

JPEG, PNG or other legacy-format images over 30 KB could be served in a modern format that is much smaller.

What triggers this issue

• JPEG, PNG, BMP or TIFF images over 30 KB.

Why it matters

WebP is typically 25–35% smaller than JPEG at the same quality, and AVIF smaller still. Every modern browser supports WebP, so it is free speed.

How to fix it

1. Convert images to WebP or AVIF, or turn on automatic format conversion in your CDN or image plugin.
2. Use <picture> with a JPEG fallback only if you must support very old browsers.

<picture>
  <source srcset="photo.avif" type="image/avif">
  <source srcset="photo.webp" type="image/webp">
  <img src="photo.jpg" alt="…" width="800" height="600">
</picture>