1. A computer-implemented method comprising: under the control of one or more computer systems configured with executable instructions, providing for display a plurality of refinement shapes configured to represent different types of shapes of a particular item available for selection by a user; causing a plurality of images of inventory items to be associated with at least one of the plurality of refinement shapes based at least in part on similarities between a first plurality of texture histogram descriptors associated with the refinement shapes and a second plurality of texture histogram descriptors associated with the inventory items; receiving information for a search request specifying at least one of the refinement shapes; and providing search results including at least a reference to at least one of the images of the inventory items associated with the at least one of the refinement shapes specified in the search request.