• Progressively enhance your website using modern picture formats like webp and avi using the <picture> element. As <picture> allows browsers to skip images they do not recognize, you can include images in your order of preference. The browser selects the first one it supports.

<picture>
 <source srcset="img/photo.avif" type="image/avif">
 <source srcset="img/photo.webp" type="image/webp">
 <img src="img/photo.jpg" alt="Description" width="360" height="240">
</picture>

• https://www.smashingmagazine.com/2021/09/modern-image-formats-avif-webp/#progressive-enhancement