Still, "backwards compatible extensions to the legacy JPEG standard". So there's that.

That's what polyfills are for.

Loading a large js library to transcode images in the browser to display them, nice idea /s

Images are much bigger than javascript libraries. So by comparison it's a small library. And you're probably decoding, not transcoding.

You want to get browser support, but a gap-filler can keep you from waiting forever to reach 99.9%. And sometimes bandwidth use is more important than clunkiness.

The FLIF one actually seems to work semi-well. Not as fast as native JPG or PNG or anything but works ok.

https://uprootlabs.github.io/poly-flif/

Being backwards compatible is JPEG XT's tentpole feature.

If no browsers support the extra bits, what's the point?

Because then people can just start using XT without any ill effects. So that’s a definite advantage.

As soon as you have some usage browser vendors will then be much more willing to support it.

Please see the W3C Patent Policy regarding Web standards.

https://www.w3.org/Consortium/Patent-Policy-20040205/

> The goal of this policy is to assure that Recommendations produced under this policy can be implemented on a Royalty-Free (RF) basis.

The browser scene is very different these days. Browsers are evergreen or yearly updated.

So are creation tools such as Adobe’s.

JPEG XR is only supported by IE (since version 2011) and Edge before the switch to Blink/Chromium. Webp is supported by everyone except Safari and IE, but Safari and mobile Safari have about 15-20% combined market share.

New formats are basically only relevant if they get blessed by Google/Chrome, and even then you often need fallbacks for a long time.

The thing that held us back before was legacy tools and browsers. Not anymore.

If we can agree on a standard (hard, I know) we can star using it pretty quickly.

Many browsers support some formats that are favorites of some vendor, but the new formats are not supported cross-browser, so the benefits of switching formats are reduced and the costs are raised -- in particular, one benefit of smaller files is reduced storage cost. If you have to support JPEG for legacy and then something else for Microsoft's format and something else for Google you are increasing your storage cost, encoding complexity, etc.

I looked at alternative image formats for a photo site I was working on and never convinced myself that the benefits of switching formats was worth the trouble.