n. ~ 1. A raster graphic formed by an array of bits, each bit representing the corresponding pixel's value (light or dark). - 2. A raster image formed by an array of bytes, each byte (or bytes) representing the corresponding pixel's color; a pixmap.
A bitmap1 is necessarily a bitonal image as a bit can represent only two values. - A bitmap2 that represents shades of gray or color requiring more than one bit per pixel is sometimes called a pixmap. In Microsoft Windows conventions, a file name for a bitmap2 has the extension .bmp.