1. A digital image processing method for locating eyes on a frontal face digital image, comprising the steps of: a) obtaining a digital image of a frontal face, W pixels wide and H pixels high, grayscale, where the top left vertex of the digital image is considered as the reference source; b) detecting each eye, starting with a search subimage of the frontal face digital image, delivering approximate coordinates if both eyes have been detected, or an arbitrary predetermined value that indicates no eye detection; c) locating the iris of each eye, if both eyes have been detected, starting from the approximate coordinates, validating the frontal face on the digital image providing eye positions; or d) validating the frontal face digital image, if one or both eyes have not been detected, calculating a search subimage defined by an area resulting from centering a square of area L on the original image, where L=0.8×W, to deliver the coordinates for the eyes.