1. A method performed by a data processing apparatus, comprising: for each image of a plurality of images: identifying web pages that each include the image; receiving, for each of the web pages identified for the image, a web score generated by a ranking algorithm, the web score being a measure of importance of the web page relative to other web pages; selecting the web page having a web score indicating a highest importance relative to other web pages; determining, from each image for which a selected webpage was identified, sets of similar images from only the images for which selected webpages were identified, each set of similar images including different images that are derived from a same source image; for each set of similar images: selecting, from the set of similar images, a landing page for an image search result that depicts an image from the set of similar images, the landing page being the selected web page that includes an image from the set of similar images and has a web score indicating a highest importance relative to other web pages that respectively include each of the other similar images of the set.