Uploading images hasn't worked for anyone on lemmy.world since yesterday. Someone made a bunch of bots that spammed a bunch of CSAM to !lemmyshitpost, so the admins have temporarily shut down that sub, disabled image uploading, and made account signups by application only until they figure out a solution. It sucks, but whatever scumbag not only possesses but makes bots to spam CSAM on public forums sucks a billion times harder.