A technique for generating a representative image representing a case and radiographic interpretation information for each case includes calculating wavelet features of a plurality of images that have been taken and stored in the past. The calculated wavelet features and extracted keywords are stored in association with the stored images. The stored images are classified on the basis of the extracted keywords to generate a plurality of groups. For each of the generated groups, a centroid vector of wavelet feature-based feature vectors of respective images corresponding to the keywords is calculated and a spatial distance between the calculated centroid vector and each of the wavelet feature-based feature vectors is calculated. For each of the groups, the image for which the calculated spatial distance is the shortest and the radiographic interpretation information associated with the image is stored as a representative image of that group.
