I wanted to compare what image artifacts look like among different lossy image formats so here's a screenshot of this toot in PNG, followed by the same screenshot exported iteratively through GNU IMP at the lowest quality settings until a fixed point is reached for JXL (you won't be able to see the second one if your browser doesn't support it), WEBP, and JPG. In other words, these are the worst versions of the original PNG you could possibly see, unless you reëxport in a combination of different formats (I don't think a fixed point will be achievable for that...). I think it's pretty cool how much JXL retains legibility, and just how awful JPG is lol (why is the background a completely different colour??)
The final lossy image format Firefox supports is AVIF, which turns out does have a lossy encoder. It somehow manages to be even worse than JPG, as if someone dragged a smudge tool all over the post. It's impressive how literally illegible this screenshot has become
out of curiosity I decided to do the same thing using HEIC, which is only supported on Safari, so I've also attached a WEBP export of it that I (and most other people) can actually see. it's... demonic how does this happen
