Lee Daniel Crocker

Who is Lee Daniel Crocker?

Lee Daniel Crocker is an American computer programmer and poker player. He is best known for rewriting the software upon which Wikipedia runs to address scalability problems. This new software, originally known as "Phase III", went live in July 2002 and became the foundation of what is now called MediaWiki. Until 2012, MediaWiki's Subversion code repository was still named "phase3".

He was involved in the creation of the GIF, JPEG, and PNG image file formats, and appears as a co-author of the PNG specification. He invented the per-scanline variable pre-filtering compression method used by PNG, the sum-of-abs heuristic used by many encoding programs, and proposed an early version of the Adam7 algorithm, using 5 passes rather than 7.

In June 2010, Crocker and others won the USENIX Advanced Computing Technical Association STUG award for contributions to the Wikipedia software.