JPEG XL faces fierce competition from AVIF. And Google. A bit of bothUpdate about JPEG XL support and why it's a mixed bag: https://x.com/nixcraft/status/183...
It’s only backwards compatible in that it can re-encode existing jpeg content into the newer format without any image loss. Existing browsers and apps can’t render jpegXL without adding a new decoder.
Legacy client support. Old devices running old browser code can’t support a new format without software updates, and that’s not always possible. Decoding jxl on a 15yo device that’s not upgradable isn’t good UX. Sure, you probably can work around that with slow JavaScript decoding for many but it’ll be slow and processor intensive. Imagine decoding jxl on a low power arm device or something like a Celeron from the early 2010s and you’ll get the idea, it will not be anywhere near as fast as good old jpeg.
It’s only backwards compatible in that it can re-encode existing jpeg content into the newer format without any image loss. Existing browsers and apps can’t render jpegXL without adding a new decoder.
Why is that a negative?
Legacy client support. Old devices running old browser code can’t support a new format without software updates, and that’s not always possible. Decoding jxl on a 15yo device that’s not upgradable isn’t good UX. Sure, you probably can work around that with slow JavaScript decoding for many but it’ll be slow and processor intensive. Imagine decoding jxl on a low power arm device or something like a Celeron from the early 2010s and you’ll get the idea, it will not be anywhere near as fast as good old jpeg.
But how is that different to any other new format? Webp was no different?