One particularly interesting (to me, at least) approach using progressive decoding was described by Jake Archibald ( https://jakearchibald.com/2025/present-and-future-of-progres... ).

If browsers extended `srcset` with support for HTTP Range requests, we could use a progressive-encoded jpg (xl or not) file as the source for multiple detail levels.

A device with a small screen would request the first 10kb of the image, while one with a medium screen might fetch 40kb.

The big advantage of that - for sites with many images - is a much better cache hit-rate for a given CDN spend.

Additionally, if you've already fetched a small version of an image and then want to view a bigger version, you've already got partial content downloaded & can fetch only the rest of the file.