anonymity

I wonder how easy it would be to find a photo of somebody?
Assume you’re given collections of photos from a group of friends. Each collection is separate and unlabeled. And you know the names of the photographer for each set. How hard would it be to find a photo of each photographer?
Use flickr as an example. Assume I was a privacy fanatic and didn’t tag any photos. If you went to my account, you could look at my profile, and see which other members I consider to be close connections (“friends” and “relatives”).
I’m assuming that in general, the least likely person to show up in each photographer’s collection is themselves. (barring special projects like flickr’s “365”). But that there’s a good chance you show up in the photos of you close connections.
Looking briefly at my collection, I have a fair number of pictures of certian people. (ie, Kier, Stephanie, Shannon). Even without knowing who they are, you can remove them from consideration, not only from my collection of photos, but from the collections of everyone else as well.
How long can you keep narrowing it down? Can you come reasonably close to finding my photo?
(just an example… i label all my photos. could find picture of me in no time flat).