Flatbed image scanner. View of a desktop flatbed scanner with its lid open. The flat glass bed of the scanner is seen (lower centre) on which images are placed. On the lid a light source is visible. Photographic transparencies or prints are laid flat while a thin beam of light scans across the image. The photograph is interpreted as a digital signal that consists of tiny but numerous bits of data. This electronic data is stored on computer and can be reassembled to produce the image on a computer screen.