18. A non-transitory, computer-readable media comprising instructions operable, when executed by one or more computing systems, to: extract one or more features from a photo; calculate 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 apply one or more policies to the photo based on the engagement metric.
28. The media of claim 18 , the instructions operable to extract one or more features comprising instructions operable to apply one or more facial recognition algorithms to the photo, wherein one of the one or more features comprises the size of the faces detected in the photo.