Bitmap

A bitmap is a data file or structure which corresponds bit-for-pixel with an image displayed on a screen, sometimes in the same format as it would be stored in the display's video memory or maybe as a device independent bitmap.

Description
A bitmap is characterized by the width and height of the image in pixels and the number of bits per pixel which determines the number of shades of grey or colors it can represent. A bitmap representing a colored image (a "pixmap") will usually have pixels with between one and eight bits for each of the red, green, and blue (RGB) components, though other color encodings are also used. The green component sometimes has more bits that the other two to cater for the human eye's greater discrimination in this component.