Lower bandwidth for who? When images are cached on other instances, it allows two things:

• Load sharing. The original instance doesn’t have to serve the whole fediverse, but only its own users + 1 request per other lemmy instance.
• Data availability through redundancy. If the original instance goes down, the cached image is still viewable on other instances.

can the instance even support federation with a multimillion user federation? Just look at the fedilags recently.

“The instance” from the question isn’t Meta’s, it’s sh.itjust.works, or any other “small” instance. Federation mostly works by mirroring a lot of data from instance A (i.e. Meta) into instance B (i.e. sh.itjust.works). If instance A broadcasts a lot of data, instance B might get overloaded.

For a more user-friendly (IMO) alternative, altough not open source, there is Resilio Sync. The main difference with Syncthing is that you don’t introduce clients to each other; you just share folders.

When lemmy.world will disappear, that’ll be a lot of communities (and valuable information) that go with it.

deleted by creator

I must say it was a funny rant to read (and I 100% agree with you)

Edit: though i quickly looked at the code and it seems that the regex is customizable? https://github.com/LemmyNet/lemmy/blob/e181f4f41d61832f1278775179b6743699f8af12/crates/api_crud/src/site/update.rs#L95

(Edit: updated the link as a github permalink)