In computer graphics and digital photography, a raster graphic or bitmap image is a dot matrix data structure that represents a generally rectangular grid of pixels (points of color), viewable via a bitmapped display (monitor), paper, or other display medium. Raster images are stored in image files with varying dissemination, production, generation, and acquisition formats.
The printing and prepress industries know raster graphics as contones (from "continuous tones"). The opposite to contones is "line work", usually implemented as vector graphics in digital systems.
A bitmap is a rectangular grid of pixels, with each pixel's color being specified by a number of bits. A bitmap might be created for storage in the display's video memory or as a device-independent bitmap file. A raster is technically characterized by the width and height of the image in pixels and by the number of bits per pixel.