…With the arrival of computing, the Iconclass system, a highly complex way of classifying the content of images, with 28,000 classification types, and 14,000 keywords, was developed in the Netherlands as a standard classification for recording collections, with the idea of assembling huge databases that will allow the retrieval of images featuring particular details, subjects or other common factors. For example, the Iconclass code “71H7131” is for the subject of “Bathsheba (alone) with David’s letter”, whereas “71” is the whole “Old Testament” and “71H” the “story of David”. A number of collections of different types have been classified using Iconclass, notably many types of old master print, the collections of the Gemäldegalerie, Berlin and the German Marburger Index. These are available, usually on-line or on DVD.[8][9] The system can also be used outside pure art history, for example on sites like Flickr.[10]…

via Iconography – Wikipedia, the free encyclopedia.