Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior results compared with generic data compression methods which are used for other digital data.
Comparison of JPEG images saved by Adobe Photoshop at different quality levels and with or without "save for web"
Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. It is a form of digital imaging based on gathering visible light.
The Mars Orbiter Camera selected by NASA in 1986 (costing US$44 million) contains a 32-bit radiation-hardened 10 MHz processor and 12 MB of DRAM, then considered state of the art.