Right now all audits to plain Drupal websites get the warning "Serve images in next-gen formats".
Since this something increasingly important to all Drupal installs, we should consider supporting some of the "next-gen" formats.
- Imagem from auditing drupal.com
The formats that Google Lighthouse indicates are JPEG 2000, JPEG XR, and WebP that still have limited browser support.
In order to make it work on all Drupal supported browsers, we would need to have a fallback strategy.
We would need to be able to also generate images on that formats from the image style, and then make them available on the generated markup.
<picture>
<source srcset="img/yourImage.webp" type="image/webp">
<source srcset="img/yourImage.jpg" type="image/jpeg">
<img src="img/yourImage.jpg" alt="Your image">
</picture>