1. A representative image display device that selects representative images according to grouping results of a plurality of images and sub-clusters and displays the selected representative images on a display, the images being grouped into the sub-clusters such that each sub-cluster includes similar images, the sub-clusters being grouped into a plurality of clusters such that each cluster includes similar sub-clusters, the representative image display device comprising: a cluster selection unit operable to select one or more of the clusters as representative clusters; a sub-cluster selection unit operable to select, from each representative cluster, M sub-clusters as representative sub-clusters based on first likelihoods of the sub-clusters in the representative cluster, each first likelihood indicating accuracy of the grouping result of the corresponding sub-cluster (M is an integer satisfying a relationship 1≦M≦the number of the sub-clusters in the representative cluster); and a representative image selection unit operable to select, from each representative sub-cluster, N images as representative images based on second likelihoods of the images in the representative sub-cluster, each second likelihood indicating accuracy of the grouping result of the corresponding image (N is an integer satisfying a relationship 1≦N≦the number of the images in the representative sub-cluster).