I'm not one for passive-aggressive "hints" - complete with "birthday" cards! -- but a copy of the Sth Park episode with Miss Choksondix gross nipples making their appearance beneath the bottom of her shirt as she reaches up to write on the blackboard my be just the ticket.

Or better still, when all looking at the photos that she's discarding, simply respond to her "Oh I don't like the way I look in this photo" with "Is that because your boobs are not-so-elegantly grazing your knees?!"

when opportunity knocks.....