1. A system, comprising: one or more computers including one or more storage devices storing instructions that when executed by the one or more computers cause the one or more computers to perform operations comprising: receiving a digital image and a digital video; extracting one or more features from the digital image; identifying one or more representative scenes in the digital video; selecting, for each representative scene, a representative frame from a portion of the digital video that corresponds to the representative scene; extracting one or more respective features from each representative frame; comparing the one or more features extracted from the digital image to the one or more respective features extracted from each representative frame from the portion of the digital video that corresponds to each representative scene; and classifying the digital image as related to the digital video based on the comparison of the one or more features extracted from the image to the one or more respective features extracted from each representative frame from the portion of the digital video that corresponds to each representative scene.