My thoughts are based on a few assumptions - if some of these don't apply, I'm sorry!!
First, I would hope and assume that most people in the cast get on. In this day and age, that means adding each other on Facebook. Then, one would assume the person who has uploaded the photos would tag the correct people in the photos. Once the person/ people in the photo's see them, they can always de-tag themselves or ask for the photos to be removed. Job done, self-regulation!
However, if the photo's aren't being removed, then maybe (only if the people involved speak to you about it) you could have a word with the photographer.
2p!!
Chris