PNG?

Justification

Why PNG? And what is PNG actually?

To start with the second question: PNG is a format to store pictures in. You could compare it to GIF or JPEG. The letters PNG stand for Portable Network Graphics.

PNG was invented by a bunch of Internet fanatics after the computer company Unisys had announced they were going to cash in on commercial use of their LZH compression patent. Compression helps to make files smaller. LZH is a popular compression method. It is being used amongst others in GIF, ZIP and LHA file formats.

The soon to be members of the PNG group recognised the potential financial disaster for the end user. Commercial programs would become more expensive, because the makers of these program would have to acquire a licence from Unisys per copy sold. The use of pictures on the Internet would become less attractive.

Nowadays, most producers of graphical applications have done the sensible thing and have gone ahead with the popular GIF format anyways. Most end users couldn't care less, as they steal their software instead of buying it.

Nevertheless there are some good reasons to use PNG. So why should you use PNG?

First, something can be said in favour of freely usable file formats for popular applications. Such formats are for instance JPEG, HTML and RTF. One such format for so called line art is PNG. Initiatives as the PNG one should be encouraged by the end user (the information provider on the Internet).
Second, PNG offers better compression than GIF. Typically, my own pictures are two-third the size of their GIF counterparts. A careful estimation shows that the use of bandwidth on the Internet can be reduced by a noticeable amount if everybody would use PNG instead of GIF. To look at it from the information provider's point of view: One can put 30% more pictures on one's homepage or use pictures that are 30% larger without reaching the limit of disk usage (provided the ISP uses such a limit).
The PNG format has more to offer. For instance, it can be used for 24 bit pictures (16+ million colours!). The structure is a bit more logical. You can use a text viewer to get some information from a PNG file. Author name and description are saved as plain text.

Not everything smells of roses when considering PNG. Lately, animated GIFs are all the rage on the Internet. Unfortunately there is no animated PNG format and there will never be an official one. The PNG consortium does allow extensions to the format, but this may lead to a multitude of animated PNG formats being made (which is bad, because there will be no standard). In this case it probably is better to still use GIF.

The PNG consortium have their own homepage at http://graphicswiz.com/png/.

Branko Collin, April 1997

Updates

14 September 1999

The home page of the PNG group used to be at http://www.wco.com/~png/.
A new controversy has arissen: Unisys now wants to charge every website that uses GIFs that were made with suspect software (i.e. software that has no Unisys license for LZW compression) 5000 US Dollar.
The PNG group has started developing an animation format to help replace animated GIFs. This format is called MNG.

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