1. A method comprising: partitioning a plurality of images of an image space into a plurality of coarse clusters, the partitioning based at least in part on signatures of the plurality of images determined from compact descriptors of the plurality of images; creating a refined cluster that includes one or more images of an individual coarse cluster based at least in part on pair-wise comparisons of the compact descriptors of images of the individual coarse cluster; and identifying the refined cluster as a set of duplicate images.