JPEG is now almost 30 years old. Compared to other standards, it has done incredibly well. At this point, however, we have gigantic 8K screens and tiny wristwatch screens, and everything in between. We have displays that are very common an very widely deployed that are much better than the best displays of the early 90s when JPEG was introduced.
Still images need higher image quality as compared to moving images. A format like GIF attempts to do both.
What we are looking for in a JPEG replacement is: all the features of JPEG, including progressive JPEG files, with better resolution, better color depth, better compression, and an alpha channel. If we get any additional features out of it, great.
As someone who actually read all of the slides from the link, it appears that JPEG XL meets all of the above requirements. Images in JPEG XL will look better than JPEG and can be smaller in size at the same image quality or sometimes better.
It can be used for photos, illustrations, rendered images, screen shots, UI elements, medical images, and more.
Finally, it has one interesting feature allowing a single image to be "squeezed." This could eliminate the need for some image hosts to provide multiple versions of the image on the Internet. No more "click here for the larger image." Instead, that can be done by the user or user agent.
With the feature list looking great, the next question would be patents. At this point, it appears to be patent-free.
The final question is the feasibility. We need an freely-available open source reference implementation.
Once that is done, get ready for the JXL format revolution.
Finally.
