Editing Digital image (section)

===Digital image compression===
{{Main|Image compression}}

An important development in digital [[image compression]] technology was the [[discrete cosine transform]] (DCT), a [[lossy compression]] technique first proposed by [[N. Ahmed|Nasir Ahmed]] in 1972.<ref name="Ahmed">{{cite journal |last=Ahmed |first=Nasir |author-link=N. Ahmed |title=How I Came Up With the Discrete Cosine Transform |journal=[[Digital Signal Processing (journal)|Digital Signal Processing]] |date=January 1991 |volume=1 |issue=1 |pages=4–5 |doi=10.1016/1051-2004(91)90086-Z |bibcode=1991DSP.....1....4A |url=https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |access-date=2019-09-14 |archive-date=2016-06-10 |archive-url=https://web.archive.org/web/20160610013109/https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |url-status=live |url-access=subscription }}</ref> DCT compression is used in [[JPEG]], which was introduced by the [[Joint Photographic Experts Group]] in 1992.<ref name="t81">{{cite web |title=T.81 – Digital Compression and Coding of Continuous-Tone Still Images – Requirements and Guidelines |url=https://www.w3.org/Graphics/JPEG/itu-t81.pdf |publisher=[[CCITT]] |date=September 1992 |access-date=12 July 2019 |archive-date=30 December 2019 |archive-url=https://web.archive.org/web/20191230093239/https://www.w3.org/Graphics/JPEG/itu-t81.pdf |url-status=live }}</ref> JPEG compresses images down to much smaller file sizes, and has become the most widely used image file format on the [[Internet]].<ref>{{cite web |title=The JPEG image format explained |url=https://home.bt.com/tech-gadgets/photography/what-is-a-jpeg-11364206889349 |website=[[BT.com]] |publisher=[[BT Group]] |access-date=5 August 2019 |date=31 May 2018 |archive-date=5 August 2019 |archive-url=https://web.archive.org/web/20190805194553/https://home.bt.com/tech-gadgets/photography/what-is-a-jpeg-11364206889349 }}</ref>