the line between amateur and professional, primitive and sophisticated is not just harder to draw with photography than it is with painting—it has little meaning. Naive or commercial or merely utilitarian photography is no different in kind from photography as practiced by the most gifted professionals: there are pictures taken by anonymous amateurs which are just as interesting, as complex formally, as representative of photography’s characteristic powers as a Stieglitz or an Evans.
— Susan Sontag, On Photography, 1977