1. A method comprising, by a computing device: accessing an image associated with an online social network, wherein the image portrays at least a first person; calculating, for each user in a first set of users of the online social network, a facial-recognition score with respect to the first person portrayed in the image, wherein the facial-recognition score is based at least in part on: a social-graph affinity associated with the user; and a facial-representation associated with the user, wherein the facial-representation associated with the user is compared with the image; and tagging the image with a particular user in the first set of users based on the calculated facial-recognition scores.