To be completely honest, if one of my friends took a pic of something in my place, and emailed it to a nonmutual friend and made fun of it, I would really not care. But, bringing it to mutual friends and making a big thing of it would bother me. It would also bother me if someone was making repeated snarky comments about me and obviously didn't like me much, when I thought they did.
So, I'm for telling Jenny after finals, because this seems like something she should know--that her friend doesn't actually like her boyfriend at all, and maybe not her all that much.
I am also slightly bugged by jealousy accusations, just because it seems like it's something everyone jumps to and it's often not true. I am in a very happy relationship and would still eye-roll at some over the top displays. People can not like something without having any motive behind it--if I mock someone's pants, it's not because I secretly want them, and I don't think anyone would immediately think so, so I'm not sure why it's *always* assumed that's the case with PDA.