Lee Daniel Crocker

Lee Daniel Crocker (born July 3, 1963) is an American computer programmer best known for rewriting the software on which Wikipedia runs to address scalability problems. That software, first called Phase III, went live in July 2002 and became the foundation of what is now called MediaWiki; the code repository kept the name phase3 until the move from Subversion to Git in March 2012. Crocker is also a co-author of the PNG specification and was involved in the creation of the GIF and JPEG image file formats. He invented the per-scanline variable pre-filtering compression method used by PNG, along with the sum-of-abs heuristic that many encoding programs use to choose a filter. In June 2010 the Software Tools Users Group named him among the major contributors to MediaWiki when it gave its award to MediaWiki and the Wikimedia Foundation.