bitmapraster

Bitmap raster refers to a digital image representation that uses a grid of picture elements, or pixels. Each pixel holds color information, so the final image is determined by the arrangement and values of all pixels in a rectangular matrix. The size of a bitmap is defined by its width and height in pixels and its color depth, often 8, 16, or 24 bits per pixel, with higher depths used for richer color or HDR images. The uncompressed data for a bitmap is roughly width × height × color depth, before any compression.

Raster images are resolution dependent; enlarging them can produce blocky or blurred results because new pixels must be interpolated from existing ones. They are well suited for representing complex, continuous-tone imagery such as photographs. In practice, bitmap images are stored in formats that may apply lossless or lossy compression. Common formats include BMP, PNG, JPEG, TIFF, GIF, WebP, and HEIF. Lossless formats preserve exact pixel data, while lossy formats reduce file size by discarding some information.

Color models frequently used with bitmaps include RGB, RGBA, and indexed color. Raster images are produced by cameras, scanners, and software rendering, and they are widely used on the web and in digital media. They contrast with vector graphics, which describe images by geometric shapes and are scalable without quality loss.

See also: raster graphics, bitmap, image compression, pixel.