The idea is that if image hosts want they can host the image + a torrent file and hand out a magnet that can be used independently both by clients that implement magnets and clients that don't.
Basically zero-cost pseudo-decentralized images with WebTorrent and WebSeeds: https://user-images.githubusercontent.com/1653275/222025570-6f893106-9c35-4862-bea6-10e518c91b92.mp4
Discussion
In the worst case we get what we have today already: just images hosted by a server. In the wonderful p2p decentralized case we get people seeding content to each other and hashes being verified.
Now I am thinking that it might be a good idea to come up with a new URL scheme that is backwards-compatible.
Instead of magnet: