avif / webp test

This is the demo page of webp-inline-support repository and of this blog post and this blog post.

>= 2021: CSS avif/webp background with image-set (progressive enhancement)

< 2021: CSS avif/webp background image

`picture` elements

`picture` element with avif as first source

Demo Image with avif/webp/png source chain

`picture` element with webp as first source

Demo Image with webp/avif/png source chain

`picture` element with png as first source

Demo Image with png/webp/avif source chain