1. A method comprising: performing, by one or more computing devices: for each of a plurality of patches in a first image, locating a corresponding similar patch in a second image based on one or more similarity measures; determining a score for each of the plurality of patches with respect to its corresponding similar patch, wherein determining the score comprises determining one or more of a divergence metric or a distance metric; selecting at least one saliently different crop in the first image relative to the second image based at least in part on the determined score; and generating at least one thumbnail image for the first image based at least in part on the at least one saliently different crop.