The Support Issue
Pretty neat file format, eh? Begs the question "why doesn't Microsoft provide full support for it?" One major reason is the fact that Unisys and Compuserve never followed through on their GIF licensing fee plan. GIF and JPEG were already in widespread use so the need for an alternative format faded away. Another issue may be the file size of a PNG graphic with Tranparency as compared to alternative formats. The red button above is 850 bytes as a transparent GIF and 1.7 K as a 24-bit PNG with Transparency. 2 or 3 years ago this might have been an issue but with the widespread availability of high-speed internet connections today it is becoming less so. Also... if you can replace 5 or 6 GIFs with one PNG you have, in effect, cut the load time for your graphics substantially

The support issue might also have to do with the priorities of the development team who designed the PC version of Internet Explorer 6. Improvements and enhancements to the appearance and operation of the browser make a bigger splash than the incorporation of PNG support. One appeals to hundreds of thousands, if not millions of internet users while the other appeals to a small number of individuals in the development community. Also, as was illustrated, the use of PNG doesn't take away from the appearance of graphics in an HTML document, but instead, changes the way that those graphics are created. Again... this is something that will make little difference to the end user of a web browser. Microsoft probably realized this and concentrated on improving the aspects of the browser that would have the most impact on those who will end up using it. Makes sense. Unfortunately, it still leaves the designer hanging. It also leaves you wondering why it is that the team responsible for the current version of Internet Explorer for the Mac had been able to incorporate full support while the PC development team passed it over? Both of these teams work for the same company and on slightly different versions of the same product. Did they not interact? Why would one implement PNG and not the other? Interesting questions. Something I can ponder while I'm trying to minimize the fringe in my transparent GIFs.

For more information on the specifications and history of the Portable Network Graphic File Format please visit.... http://www.libpng.org/pub/png/. The site is maintained by Greg Roelofs, one of the creators and strongest proponents of PNG.

For the particulars on colour palettes, 8-bit and 24-bit graphics, and web design refer to the various related courses on TrainingTools.com or use your search engine of choice.