Despite the pervasiveness (it will show photos from the beginning of Facebook), it's astoundingly simple to use.
All you have to do, is type "photos liked by..." with your intended target's name at the end. For instance, if I were friends with Russel Crowe (which I am, just not on Facebook) I would type in "photos liked by Russell Crowe" into the search bar, and then subsequently bask in the smorgasbord of digital adulation doled out by the Aussie actor -- as long as the photos aren't private of course. That's the bad news.
But here's the good news: you can do this for almost every aspect of Facebook, "posts liked," "events attended," and anything else your creeping little heart desires to inquire about.