Okay - it would have been nice to learn where the proposal fails, but I understand that I can't access your expertise for free. Take it easy!
It really feels like you didn't read my post. I specifically called out caching as a concern, and even if we see more requests, they will be cheap to serve.
I could use a primer on Lemmy, since frankly I don't know the culture all that much. If you have a pointer to something in mind, I'd appreciate it.
FWIW, I've gotten banned from two forums already (ha) so you aren't kidding. 😜
It's annoying to have to create a new account since federation from mbin to Lemmy doesn't seem to work across many instances. That and adding a thumbnail to many Lemmy communities simply strips the shared link.
One thing that I neglected to mention is that since the SRI hashes are calculated, previews can be cached by peers other than the originating host - since they are verifiable, anyone can pass them along and the client can verify the payload.
Not something I really fleshed out in discovery, but if there is interest, that might make it more production ready.