A computer file in which each pixel contains one bit of image information. Sometimes used interchangeably with raster. Generally bitmap graphics are used on the web because of their low resolution.
A graphic image or text formed by a pattern of dots or pixels. Examples include scanned documents and printed newspaper pictures. An electronic graphic file where each minute item (dot) in the graphic picture is represented by a single (or several for colour) bit of information in the file. Thus a picture with 8,000 bits of information would produce a 1,000- byte file. (1 byte = 8 bits). These files cannot be scaled in the way that vector-based images can.
A bitmap is a grid of pixels having individual color values. The term bitmap graphics is used to define digital images such as scanned photos, or artwork created in image-editing applications. Since bitmap images are resolution dependent unlike vector images, you lose detail when you scale bitmaps. The loss of detail is especially noticeable when you scale up an image. The result has either jagged edges or is blurred. On the other hand, bitmap graphics offer precise, pixel-level control on images. You can change the color of individual pixels or in other words, freely paint on an bitmap image. See also: Vector Graphics