1. A method comprising: by one or more computing devices, receiving a set of related images associated with a primary user, wherein a face appears in each of the related images; by one or more computing devices, selecting one or more candidates who may be identified with the at least one face, wherein each of the candidates is a user of a social network, and wherein for each of the candidates a computed measure of affinity of the primary user's interest in the candidate exceeds a threshold, and wherein the measure of affinity for each of the candidates is computed based on a predictor function; by one or more computing devices, for each of the related images, determining a candidate score for each of the candidates, wherein the candidate score for a particular candidate represents a likelihood that the particular candidate corresponds to the face, the candidate score being based at least in part on: the computed measure of affinity for the particular candidate; and a facial recognition comparison of the particular candidate to the face; by one or more computing devices, for each of the candidates, determining a facial-recognition score, wherein a facial-recognition score for a particular candidate is based on an aggregate value of a plurality of candidate scores for the particular candidate; and by one or more computing devices, determining a winning candidate to identify the face based on the facial-recognition scores, wherein the particular candidate is determined to be the winning candidate for a particular image among the plurality of images only when the particular candidate has been determined to be a winning candidate in at least a minimum number of images preceding the particular image in the set of related images.