 The pixels, or color samples, that form a digitized image (such as a JPEG file used on a web page) may or may not be in one-to-one correspondence with screen pixels, depending on how a computer displays an image.In computing, an image composed of pixels is known as a "bitmapped image" or a "raster image".The word "raster" originates from television scanning patterns, and has been widely used to describe similar halftone printing and storage techniques.