1. A method for automatically classifying a digital radiographic image, comprising the steps of: acquiring the digital radiographic image comprised of a matrix of rows and columns of pixels; segmenting the image into foreground, background, and anatomy regions; classifying a physical size of the anatomy region; generating an edge direction histogram of the anatomy region; classifying a shape pattern of the edge direction histogram; and categorizing the image based on the physical size classification and the shape pattern classification.