Mention GIF transcode feature in README

README.md

@@ -78,6 +78,7 @@ npm run build
 - Generates multiple sizes of each image and uses them in **`srcset`**.
 - Generates a **blurry placeholder** for each image (without adding an HTML element or using JS).
 - Transcodes images to [AVIF](<https://en.wikipedia.org/wiki/AV1#AV1_Image_File_Format_(AVIF)>) and [webp](https://developers.google.com/speed/webp) and generates `picture` element.
+- Transcodes GIFs to muted looping autoplaying MP4 videos for greatly reduced file size.
 - **Lazy loads** images (using [native `loading=lazy`](https://web.dev/native-lazy-loading/)).
 - **Async decodes** images (using `decoding=async`).
 - **Lazy layout** of images and placeholders using [`content-visibility: auto`](https://web.dev/content-visibility/#skipping-rendering-work-with-content-visibility).