Sounds like a young person, for sure, but you were at least a senior in h.s. before you had a yearbook, right? I always assumed JonBenet or Burke did the x's and drew around their dad's picture.
Haven't we all agreed that some of the acquaintances could have been carrying on some kind of game and the Ramseys just didn't believe JonBenet, or that, due to something Nedra said, they figured it was "only a little bit" and let it go on? Of course pedo rings could have been exchanging pictures of her, and could also have been involved. We've agreed Karr didn't do it but could have been with someone, and maybe that someone knew someone among the friends. I really think it was someone who was at the party on the 23rd, and JonBenet was putting her foot down, trying to call 911 because grownups, not even her parents, weren't taking her seriously.