1. A computer-implemented method comprising steps of: receiving a query, wherein the query identifies a set of one or more query terms; 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; for each particular sample image in the set of sample images, selecting, from the image corpus, a separate set of candidate images that are visually similar to that particular sample image, and associating that set of candidate images with the particular sample image; determining that a first set of candidate images, associated with a first sample image of the set of sample images, and a second set of candidate images, associated with a second sample image of the set of sample images, both contain at least a threshold number of candidate images in common; determining that a third set of candidate images, associated with a third sample image of the set of sample images, contains less than the threshold number of candidate images in common with the first and second sets of candidate images; and in response to determining that the third set of candidate images contains less than the threshold number of candidate images in common with the first and second sets of candidate images, generating an aggregated set of images based on the first and second sets of candidate images; wherein the steps are performed by at least one computing device.