Most computer graphics images are presented to the user on some kind of raster display. Raster displays show images as rectangular arrays of pixels. A common example is a flat-panel computer display or television, which has a rectangular array of small light-emitting pixels that can individually be set to different colors to create any desired image. Different colors are achieved by mixing varying intensities of red, green, and blue light. Most printers, such as laser printers and ink-jet printers, are also raster devices. They are based on scanning: there is no physical grid of pixels, but the image is laid down sequentially by depositing ink at selected points on a grid.
Pixel is short for “picture element.”