These photos are legal. The actions of the user who favorited these is also legal (although incredibly disgusting). I did not want photos of my child to appear here. So, this is what I did:
1) Blocked the user. This means my photos would no longer appear in the list. However, if your photos are viewable to the public, this means they can still be viewed, just not favorited.
2) Contacted Flickr: I reported this user, and within a couple of hours, the user was taken down.