Nothing, really, to be honest. You'll find that a handful of people on the higher end of the points list are guilty of one or more of those (or just rushed, poorly-cropped/rotated images). It's not unheard of for someone to lose their self-approval privileges but I don't think it happens that often.
I'm sure this won't get seen by a wide enough audience of folks that need to see it, but one way to make sure your images don't disappear (by the way, this isn't aimed at you, OP!) is to look at the release notes before uploading images. Once in a while I have to clean up hobby sets with retail images because the uploader didn't realize that the notes mentioned the two different versions and where they should go.