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>
Comments
Comment #2
cilefen commentedCould you please add to the issue a definition of these formats?
Comment #3
rfmarcelino commentedComment #4
rfmarcelino commentedAdditional info added.
Comment #6
jaimeah commentedHere is an explanation of the formats. You can see different formats are compatible with different browsers, which seems to be the major difference:
Comment #8
mgiffordThis is something that would be really useful to reduce the CO2 footprint of sites using Drupal. Could really help with performance too (obviously).
Would be nice if this were centralized in Drupal so that whenever the next fast format comes out, it can be more easily adopted.
Comment #9
phenaproximaComment #14
mgiffordComment #15
mgiffordComment #16
mgiffordComment #19
sd123 commented@jaimeah: I would skip support for JPEG XR and JPEG 2000. Instead add support for AVIF and for sure JPEG XL which allows for backward compatibility with JPEG.
Comment #20
mgiffordDoesn't seem to be a lot of support for JPEG XL https://caniuse.com/?search=JPEG%20XL
AVIF & WebP look ready to roll though:
https://caniuse.com/?search=avif
https://caniuse.com/?search=webp
Also, we can build on the work of another CMS that's already moved this way:
https://wagtail.org/blog/wagtail-greener-and-leaner/
Comment #21
sd123 commentedI think both JPEG XL and AVIF support will be best to have. The first format will be better in the long run since it will allow an easy and painless transition of existing websites because of it backward compatibility features with JPEG.
Comment #22
mgiffordJust adding some additional references here about the importance of this:
Comment #23
sd123 commentedAs JPEG XL industry adoption is gaining momentum with now also Google changing their mind regarding JPEG XL and experimental support already returned to Chrome Canary, it is maybe an opportunity to focus on this now.
Comment #25
catchSee #3559944: [pp-upstream] add support for JPEG XL