ChromeならAVIFで表示されるはずだが…
.sample { width: 300px; height: 200px; background-image: -webkit-image-set( url("sample.avif") type("image/avif"), url("sample.webp") type("image/webp"), url("sample.jpg") type("image/jpeg") ); background-image: image-set( url("sample.avif") type("image/avif"), url("sample.webp") type("image/webp"), url("sample.jpg") type("image/jpeg") ); background-size: cover; }