The reason is patents. The JPEG people made sure everything they produced after JPEG proper was irrelevant for the open Web by patenting it to hell and back. (E

The reason is patents. The JPEG people made sure everything they produced after JPEG proper was irrelevant for the open Web by patenting it to hell and back. (Even JPEG is only recently freely implementable in full, because it has a better mode with arithmetic coding instead of Huffman that nobody uses in order to avoid patents.) I’ve heard there’s also a small issue where a naïve JPEG 2000 decoder would produce images that look less sharp even if they’re nominally better (cf. similar issues with H.264, mentioned at <https://news.ycombinator.com/item?id=16615962 https://news.ycombinator.com/item?id=16615962>), but the patents is the big one. Now browsers (specifically Firefox) making sure MNG (the better-designed animated sibling of PNG) never got off the ground is not such a good look for them.