A device for cropping photographs can be constructed utilizing upper and lower frames which are movable with respect to one another. Each of the frames has two edges located at right angles to one another; the frames are located one above another so that the edges of the frames define a rectilinear opening....http://www.google.fr/patents/US4460271?utm_source=gb-gplus-shareBrevet US4460271 - Cropping device
