What term is used to describe bitmap images in graphic design?

Bitmap images are best described by the term "Raster." This designation refers to images composed of individual pixels, which combine to form the complete image. Each pixel in a raster graphic can display a different color, which is essential for representing complex visual details and colors accurately. Raster images are resolution-dependent, meaning they can lose quality when scaled up due to the fixed number of pixels in the original image. This characteristic makes raster graphics particularly suitable for detailed imagery, like photographs.

In contrast, other terms such as vector describe a different type of graphic representation that relies on mathematical equations rather than pixels. Layered refers to the organization of different elements within a design project, allowing for easier manipulation but not specifically defining the image type. Similarly, composite images involve combining multiple graphical elements into a single final image but do not inherently indicate if those elements are bitmap or vector-based. Thus, "Raster" is the term that most accurately characterizes bitmap images.