Coauthor of PNG spec, developer/maintainer of libpng, on development teams for ImageMagick and GraphicsMagick. Author of pngcrush. Maintains PNG support in Firefox. Retired, father of four, grandfather of fifteen.
LICENSE: All my StackExchange contributions across all sites, except as noted within any particular contribution, are available under the standard SO/SE licensing terms (CC-BY-SA) or under the CC-0 Public Domain Dedication, at your choice.