She's holding my pictures hostage!? /:?

so basically we've been friends for quite a few years and sometimes she can be a total backstabbing bi**h for no reason! anyways, long story short I'm friends with her for now because grad is in a few weeks and I know if we're not friends she'll ruin it. My point is that she took 2 pics of me and I moved because I thought the pics were over and I look terrible. She shows them to a lot of people and when I try preventing her from showing it she says she'll send it to everyone on an email and she's like laughing. It's so annoying and I can't do anything, can I? She also does this to one other close friend. what do I do?