Raster image is essentially an electronic "photograph" of a document, consisting of millions of pixels. The brightness value for each pixel is converted to a digital representation. Unlike alphanumeric data, raster images consist of binary 1's and 0's that in themselves carry no intelligence and therefore cannot be queried in terms of what information the image represents. It is for this reason that comprehensive, accurate indexing of digital images is mandatory for efficient user retrieval access. Properly indexed electronic digital images can be displayed on high-resolution display screens, transmitted to a remote user sites, or distributed as hard copy.