1. A computer-implemented method comprising steps of: receiving a query, wherein the query identifies a set of one or more query terms; in response to receiving the query that identifies the set of one or more query terms, performing the steps of: selecting, from an image corpus, a set of three or more sample images that are associated with annotations that match one or more of the query terms; producing multiple separate sets of candidate images by selecting from the image corpus, for each particular sample image in the set of sample images, a separate set of candidate images that are visually similar to that particular sample image; from among images that belong to the multiple separate sets of candidate images, determining a set of duplicate images; wherein each image in the set of duplicate images is a member of at least two of the multiple separate sets of candidate images; and generating a response to the query, wherein the response is based, at least in part, on the set of duplicate images; wherein the steps are performed by at least one computing device.