1. An image retrieval system comprising: a database with clusters, each cluster comprising a respective set of candidate images and a cluster center which is representative for that set; entry means for entering a query image; cluster comparison means for comparing the query image with respective cluster centers to establish respective cluster similarities between the query image and the respective clusters; selection means for selecting at least the cluster with the largest cluster similarity with the query image; image comparison means for comparing the query image with the candidate images in the selected clusters to establish respective image similarities between the query image and the respective candidate images; and presentation means for presenting at least the candidate image with the largest image similarity.