As of right now, yes. That is correct. Your best bet is to go manually upload images to a hosting site such s Imgur and add the link to your post in the links section. That will format everything properly and is actually how other Lemmy apps are doing it right now, it’s just not automatic on Mlem right now. The devs have however said that they’re working on adding the functionality so it should be added pretty soon

Yes that is correct. However according to this comment it is planned for the near future https://lemmy.ml/comment/1300639