Posting someone's picture without their permission is a ban whether they've posted it on ATRL or not.
Even if you don't think it's a banful offense, bottomline is he shouldn't have made fun of a user by posting their picture.
"If you don't want your picture posted, you shouldn't post it" isn't really a good excuse, when he posted the picture in a place with friends and positive discussion. Going back to find his picture, posting it without his permission, and posting it to be abrasive to him isn't allowed and isn't really something defendable.
Although I think the whole drama behind them in general is probably petty, and should just be done with apologies.