Most Helpful Girl
You have to keep in mind that she did that to annoy, hurt and anger you – don't do her the favour. It's understandable that you're angry and embarrassed, but don't show her. It is exactly what she wants. Be the bigger person. Any sort of reaction, be it an angry comment or a comment to show you don't care, would be wrong at this point. Just completely ignore her and pretend you don't care. That will annoy her the most.
As for being embarrassed, I can understand that, I'd be, too. But see, the thing is that every single person who sees that picture with that caption will realize why she did it and what a nasty bitch she is. If anyone has reason to be embarrassed, it is her.2