1. A method comprising, by one or more computing systems: extracting one or more features from a photo; calculating an engagement metric for the photo based on the one or more extracted features, wherein the engagement metric represents the probability that one or more users will interact with the photo; and applying one or more policies to the photo based on the engagement metric.
7. The method of claim 1 , the extracting one or more features comprising applying one or more facial recognition algorithms to the photo, wherein one of the one or more features comprises the number of faces detected in the photo.