20. The computer software product of claim 19 , wherein said step of selecting one of said lexical classifiers as a reference lexical classifier, includes the step of setting the lexical classifier of a manually selected image element as the reference lexical classifier.
19. A computer software product including a computer-readable media having stored thereon computer software for selecting a sub-set of image elements of a digital image based on a visual attribute of the image element, the computer software, when run on a computer system, being configured to perform the steps of: using a database for providing a set of lexical classifiers that characterize said visual attribute; using a processor for: selecting a lexical classifier as a reference lexical classifier; determining a lexical classifier for each of said image elements; comparing the lexical classifier associated with each of said image elements with the reference lexical classifier; and selecting an image element as part of said sub-set of image elements if the lexical classifier of said image element corresponds to the reference lexical classifier.