1. A computer-implemented method to access an image that is representative of a query topic, the method comprising: receiving a request for a definitive image related to an identified query; accessing a store of editorial overrides to determine whether an editor has manually selected a definitive image related to the identified query; if an editorial override is not found, accessing an index of images that maps query subjects to images related to those subjects; ranking the potential definitive images identified in the index to sort the potential definitive images by a relative level of likelihood of being a definitive image; and selecting as the definitive image the highest-ranking potential definitive image; retrieving an image binary from an image data store that is associated with the selected definitive image; and sending a response that contains the retrieved image binary associated with the selected definitive image in response to the received definitive image request, wherein the preceding steps are performed by at least one processor.