Digital cameras have a lens, aperture, and shutter, but they do not use film. Instead, digital cameras use a solid-state device called an image sensor. Photosensitive diodes on the surface of the image sensor convert light passing through the lens into electrical impulses.
The charge from each of the photosensitive diodes is measured and converted into a digital number. The final image is composed of a series of square picture elements (pixels), each with its own numerical value.
Digital images are convenient because they do not require chemicals or paper to process. They can be displayed on a web page, sent via e-mail, stored on a computer hard drive or a compact disc, and printed on a page.