Chapter 21. PNG Format
The Portable Network Graphic format (PNG for short -- pronounced "ping") is a versatile and full-featured graphics file format that has been lurking in the shadows for several years. Despite some attractive features and the fact that it was created with web use specifically in mind, the PNG has been largely avoided by the web design community. This is primarily due to abysmal browser support and a lack of tools that can compress PNGs well enough to make them compete with GIFs.
The good news is that both browser and tool support has been gradually improving over the last several years. It remains to be seen, however, whether PNG will ever be permitted to live up to its potential.
21.1. The PNG Story
PNG was developed in January and February 1995 as an effort to find a non-proprietary alternative to GIF when Unisys threatened to enforce its patent on LZW compression and collect licensing fees from developers of GIF-supporting programs. This caused a flurry of outrage and activity on the Internet.
Days after the announcement, Thomas Boutell posted the first draft of the PNG specification to the comp.graphics newsgroup. A community of programmers then quickly cooperated in specifying and implementing an impressive list of features:
The PNG format became an official W3C Recommendation in October of 1996 (see http://www.w3.org/Graphics/PNG/). Since then, browser and software developers have given the format more attention, but there is still a long way to go.
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