Accounts could be NOINDEX until they are a certain age or get to a certain # of images, and then they get reviewed by hand. You can review by hand using crowdfl

Accounts could be NOINDEX until they are a certain age or get to a certain # of images, and then they get reviewed by hand. You can review by hand using crowdflower or mechanical turk - it's pretty easy to show the first 20 pictures (or whatever) in small, and have a large button. You can optimize the interface to make it very fast, as well. Flickr did this for a very long time, IIRC.