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.
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.