Those are literally just raw text urls. No formatting at all. Your client is deciding to try and load/embed any and every link it comes across.
Mainly you’re looking for links that end in an image file extension (.gif/.jpg/.jpeg/.png/etc) if you’re going to embed them as images in a comment/post. I doubt you’ll be able to with that client though… I don’t use lemmy/kbin on desktop so I’ve got no advice there.