1. A method of detecting bunched-together overlapping postal items, which method consists in moving the postal items on edge above a camera, and in forming grayscale images of the bottom sides of the postal items for the purpose of detecting the presence of any overlapping postal items by means of image analysis, said method further consisting in transforming each grayscale image into a binary image that causes a boundary defined by a “pale” zone to appear that represents the bottom side of at least one postal item and that extends between two “dark” zones, said boundary having a “right” first profile and a “left” second profile, and further consisting in analyzing the right and left profiles for the purpose of detecting any profile discontinuity that is indicative of the presence of overlapping postal items.