So if I were to try to scrub photos accessible to me with a valid username and password from Facebook, (btw Facebook makes millions annually off its users viewing photos) I would be hacking?
Not sure if it would be considered hacking but facebook has definitely sued and won judgments against folks who scraped data from public facebook profiles.
I did some googling, and while Facebook has sued small fare (like individual researchers) those researchers have pointed out that all the public profiles have been cached by Google's webcrawler, and they haven't sued Google (yet).