1. A method, comprising: receiving, at a computer system, a plurality of images, wherein one or more of the images are associated with one or more terms; for each of a plurality of pairs of images in the plurality of images, determining, by the computer system, a degree of similarity between the two images in the pair, including for a first image in the plurality of images determining degrees of similarity between the first image paired with one or more other images from the plurality of images; for the first image, assigning to one or more of the terms a respective weight with respect to the first image based at least in part on the degrees of similarity between the first image and the one or more other images; and selecting, by the computer system, one or more of the terms to associate with the first image based on the respective weights of the terms with respect to the first image and associating the selected terms with the first image.