Any Chromium and Firefox browser prior to version 116 will be vulnerable to this, update your browsers.
There’s some politics involved. Basically, everyone is rallying behind JPEGXL instead of WebP, but Google refuses to support JPEGXL in Chrome. The reasoning they gave is weak, so it’s assumed that they’re just trying to force the format they invented on everyone because they can.
IIRC, performance of the two formats is similar.
JPEG XL, like AVIF and HEIC and WebP, is basically a next generation format that supports much higher quality at lower file sizes compared to JPEG and PNG.
Among those four formats, JPEG XL is promising because it allows for recompression of JPEG losslessly. That means if you take an image that was already encoded as JPEG (as the vast, vast majority of images are), you can recompress with no additional loss in quality from the conversion. That’s something that isn’t true of the others.
JPEG XL also has a much higher maximum quality and specific features great for high quality image workflows (like for professional photographers, publishers, and those who need to print images). WebP, AVIF, and HEIC are good for sharing on the web, but the printing and publishing workflow support requires a few more conversions along the way.
I thought this blog post by a cloud image delivery network that played a big role in developing JPEG XL was pretty persuasive, even if they had a direct interest in JPEG XL adoption.
But aren’t jpegxl and webp meant for completely different uses? Like jpeg and png are. Jpeg is better for photos and png for graphics.
Also using “XL” in a name for an encoding which does better compression was not the smartest idea, that will surely confuse many users.
