1. A method of detecting explicit or implicit triangular compositions in photographic images, comprising the steps of: receiving a digital photographic image; analyzing the received digital photographic image on a programmed computer to extract a set of filtered line segments as candidate triangle sides and/or objects or regions as candidate triangle corners; automatically fitting triangles onto a) the set of line segments, or b) corners, or c) the set of line segments and corners to obtain fitting scores; and designating the triangles with the highest fitting score as detected triangles in the received digital photographic image.