Is she of drinking age?
And that must really be horrible to see photos like that. But...if she is 21 or older, these are her choices and her subsequent consequences to deal with.
However, someday you may want to mention to her that once those photos are posted on the internet, especially Facebook, they will forever live there for any and all potential future employers, boyfriends, and someday children to see. Facebook also owns those photos once they are posted on their website.
Lastly, if you gave your word, stick to it. That way, she (and you) knows your word is good, even if the evidence is smacking you upside the head.
Stay strong!
~T