png - Portable Network Graphics (PNG) format
PNG (Portable Network Graphics) is an extensible file format for the lossless, portable,
well-compressed storage of raster images. PNG provides a patent-free replacement for GIF
and can also replace many common uses of TIFF. Indexed-color, grayscale, and truecolor
images are supported, plus an optional alpha channel. Sample depths range from 1 to 16
PNG is designed to work well in online viewing applications, such as the World Wide Web,
so it is fully streamable with a progressive display option. PNG is robust, providing both
full file integrity checking and fast, simple detection of common transmission errors.
Also, PNG can store gamma and chromaticity data for improved color matching on heteroge-
libpng(3), zlib(3), deflate(5), and zlib(5)
PNG specification (second edition), November 2003:
<http://www.w3.org/TR/2003/REC-PNG-20031110/ PNG 1.2 specification, July 1999:
PNG 1.0 specification, October 1996:
or (as a W3C Recommendation) at
This man page: Glenn Randers-Pehrson
Portable Network Graphics (PNG) Specification (Second Edition) Information technology -
Computer graphics and image processing - Portable Network Graphics (PNG): Functional spec-
ification. ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999): Glenn Randers-
Pehrson and others (png-list).
Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996): Thomas
Boutell and others (png-list).
This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson. See png.h for conditions
of use and distribution.
The PNG Specification (Second Edition) is Copyright (c) 2003 W3C. (MIT, ERCIM, Keio), All
The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson. See the specifica-
tion for conditions of use and distribution.
The PNG-1.0 specification is copyright (c) 1996 Massachusetts Institute of Technology.
See the specification for conditions of use and distribution.
February 14, 2009 PNG(5)