WebP and AVIF and HEIC had similar advantages but also some disadvantages (honestly chief disadvantage to WebP in my humble opinion was that nothing except web browsers -- to this day -- seem to support it!).
Another important point in its favor is that JPEG XL is designed as a royalty‑free, open standard, and Google provides a perpetual, worldwide, royalty‑free patent license for its reference implementation.
Avoiding JXL (once the rollout is sufficiently complete) seems, to me, like still shipping (non-animated) .GIF files where .PNG is better and smaller.
Things in these categories have colorful packaging with spot colors, metallic inks, coatings, as well as store displays with carefully designed lighting. The added cost is justified because it increases sales. It makes sense to carry that over online.
Even if it cannot, getting the same quality as 'classic' JPEG in fewer bits is still useful. So you have:
* better quality in the same number of bits
* same quality in fewer bits
But I’m sure there are some that will say 64k of RAM is all anyone will ever need!
The cost of HDR displays is decreasing, and the data cost is minimal. (adding more bits to video actually decreases the size because the rounding errors get smaller)
Yes.
JPEG can represent "X" number of colours, but the human eye can detect Y>X colours. JPEG-XL can represent >X colours (but not as many as they human eye, Y):
* https://en.wikipedia.org/wiki/Wide_color_gamut
* https://en.wikipedia.org/wiki/JPEG_XL#Versatile_and_future-p...
It's trivial to make an image that you can see the 8-bit quantization in. Just make 256 vertical gray bars, equally spaced. In much of the image (usually the darker parts, but depends somewhat on monitor calibration) you will see the border between two values. Note that this is every single possible grey value in 8-bit RGB, so it is a proper un-dithered rendering of a gradient, and the borders you are seeing are definitely quantization artifacts.
Now, if you apply proper dithering, particularly on a high-dpi screen, you can make it look a lot better, possibly even undetectable.
And this is just with the dynamic range that is comfortable on a computer monitor! If we really want to represent vibrant images, then the glare of the sun off of shiny objects should be much brighter than the "paper white" background used in e.g. your word processor. It should be intuitive that the brightest highlight in a real-world image ought to be too uncomfortable to fill your entire monitor with...
Lastly, there's a question what and how the image gets to the browser. Sure for the images on the landing page for $LARGE_CORPORATION you have a graphic designer make everything look great, and since most people still have 8-bit displays, you'll want something that looks good on one. But what about e.g. a site for uploading photos? Are you going to quantize all of their photos before displaying them (possibly to someone with an HDR display)?