Requires obscure and non-obvious configuration tuning. Without it, files are saved to disk instead.
Transparency and animation do not work.
Source not available.

Does its job, but unfortunately messes up non jxl images in certain websites, causing them to fail to load

不支持透明、宽色域、动图。

Both the source code repository (i.e. "extension source" link) and the developer's GitHub profile have disappeared.

Partially restores what the cowardly Mozilla Foundation removed: support for the superior, industry-approved, backwards-compatible, open standard JPEG-XL.

(So much for driving standards compliance and being a meaningful alternative to monopolies, huh? Thanks, Mozilla.)

Unfortunately, animation is apparently not supported by this add-on at this time (September 2024) -- as tested on the jpeg xl test page.

Sadly it requires JS to be enabled for the webpage that embeds JXL images, i.e. when you're using NoScript you will not see JXL images, unless you've enabled JS execution for the page.

Secondly, it doesn't seem to support animated JXL.

Thirdly, Firefox has removed native JXL support (it can no longer be enabled via about:support). Shame on you Mozilla.

Thank you for this. Firefox should support jpeg xl.

Works well. Doesn't seem to support animations as you can see illustrated from this test page -- https://jpegxl.info/test-page/

Doesn't work in LibreWolf(from box, but i remember before is work), firefox all work.
But this is a crutch, the original jpegxl is converted to png and you don't get the benefit of its specification + have worse perfomance with reconverting

Site favicon not effective

Does not actually show original JXL, but seems to convert it to PNG (lossless). Complications may occur, such as with complex or unsupported metadata. But this is probably still a decent improvement (still testing), and about as good as it gets until Mozilla properly implements support for JPEG XL.

Doesn't work, images are blank.

After Googles braindead move and Mozillas braindead following of it, it's really great that this exists! :)

Does not work with JavaScript turned off.
The original jxl files are not displayed, but converted to png.

Great addon. JXL needs native Firefox support but until then this is a good solution!