The role of photo agencies remains a blind spot in the history of photography. Emerging in the beginning of the 20th century to satisfy the picture-hunger of modern man (Tschichold), they transformed photography into a commodity. As catalysts for the picture market and through the creation of systematic collections, these companies shaped our western visual culture. The 1920s, 1930s and 1990s, in particular, ushered a paradigm shift in the economy of the medium, marked by major technological developments and the rise of new markets. Taking the example of the Bettmann Archive and Corbis – one of the world’s largest photo agencies, founded by Bill Gates – the book Banking on Images inquires into the criteria used in selecting these images, the way in which the value of a commercial image bank is determined, and the concept of photography that lies behind it.