W3C: WD-png-960128

PNG (Portable Network Graphics) Specification

Version 0.93

W3C Working Draft 28-Jan-1996


This version:
http://www.w3.org/pub/WWW/TR/WD-png-960128
Latest version:
http://www.w3.org/pub/WWW/TR/WD-png
For list of authors, see Credits

Status of this document

This is a W3C Working Draft for review by W3C members and other interested parties. It is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to use W3C Working Drafts as reference material or to cite them as other than "work in progress". A list of current W3C working drafts can be found at: http://www.w3.org/pub/WWW/TR

Note: since working drafts are subject to frequent change, you are advised to reference the above URL, rather than the URLs for working drafts themselves.


Abstract

This document describes PNG (Portable Network Graphics), an extensible file format for the lossless, portable, well-compressed storage of raster images. PNG provides a patent-free replacement for the GIF format and can also replace many common uses of the TIFF format. Indexed-color, grayscale, and truecolor images are provided for, plus an optional alpha channel; sample depths range from 1 to 16 bits. PNG is robust and permits early detection of common transmission errors.

PNG is designed to work well in on-line viewing applications, such as the World Wide Web, and so it is fully streamable with a progressive display option. It can also contain gamma and chromaticity data for improved color matching on heterogenous platforms.

PNG is intended to be both highly extensible and highly interchangeable. Although incompatible private extensions are possible, it is expected that all PNG decoders will be able to read essentially all PNG files.

The proposed Internet Media Type image/png is defined by this specification.


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