Hmm, she looks familiar... Ah, yes. The infamous "facebook lost camera girl".
http://www.visipics.info/index.php?title=Main_Page
Visipics. Free! I use it to weed out dupes in my collection. You can even set the threshold of how closely or loosely it matches to find the same image at different resolutions, or even different images from the same set. It's an amazing app.
Not that I know of. It can be found on sites like FFFFound and Fantasti.cc and tumblr. I guessed she was at least 18. I wouldn't have posted it if I thought otherwise.
I'd recommend starting with Pamela Meyer's book, Liespotting; if it's anything like her website, it might be interesting. I learned about body posture and facial cues from my psych class last year--the prof actually showed us clips from "Lie to Me" in class.