1. A method of detecting explicit or implicit triangular compositions in photographic images, comprising the steps of: receiving a digital photographic image; analyzing the 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 vertices; automatically fitting triangles onto the set of line segments and/or vertices to obtain fitting scores; and designating the shapes with the highest fitting scores as detected triangles in the received photographic image.