By: Mike Tuck

December 17th, 2001

Reader Rating: 8

As a follow-on from the previous discussion of Graphics Legality [1], let's look at a real life case study of the legal questions over the GIF format...

The Birth of the GIF

In 1987, Compuserve [2] released the GIF format for graphics, as a free and open specification. In other words, any Web developer or graphics creator was free to create, post, trade, fold, spindle, and mutilate GIFs as they saw fit. The creators used the LZW (Lempel Ziv Welch) method of data compression to reduce the size of the files, and herein lies the copyright issue. Note that the LZW compression method is also used in TIFF graphics and several older file compression utilities, but because relatively few people use either TIFF graphics or these older file compression programs, I’ll focus on the usage of GIFs.

LZW was described by Terry A. Welch in the June 1984 issue of IEEE's Computer magazine. Unisys [3] held, and still holds a patent, on the procedure described in the article, but the article describing the algorithm made no mention of this. Welch, a Sperry employee, extended the work of previous developers Lempel and Ziv. Sperry Corporation was granted the U.S. patent in 1985. Sperry and Burroughs merged in 1986 to form Unisys, thus Unisys became the owner of the Sperry patents. Compuserve saw no reason to place any restrictions on GIF usage, and GIF graphics quickly became a staple of the World Wide Web. They were relatively easy to create, relatively compact, and quite flexible.

Unfortunately, the issue of patent infringement came up almost immediately. Although Unisys did not enforce their copyright for many years, the idea of the format having copyright issues at all was a cause for concern. Some Compuserve users immediately removed all the GIFs on their sites, or converted their graphics to JPEG or other formats that weren’t covered by the Unisys patents. Many other Web designers continued to use GIFs with little concern for the legalities, or were ignorant of the entire question. Compuserve quickly backed off of the issue. They claimed that they would have nothing to do with the debate, and any legal arguments were between Unisys and third parties. Interestingly, Unisys’s original patent is due to expire in 2003; no word yet as to whether Unisys intends to extend their patent.

Unisys Enforces its Copyright

Unisys did not begin to enforce its copyright until December 1994, when it announced that, as it owned the compression method used to make GIFs, any Websites that used GIFs not produced by Unisys-licensed software must pay the company a staggering $5,000. Unisys required:

The idea came under fire immediately. According to the outraged owners of BurnAllGifs [4], an organization opposed to Unisys’s assertion of control over the GIF format:

When Unisys first announced that it would begin to enforce its copyright claims, they stated that they had no interest in pursuing patent infringement claims on anyone using GIFs for non-profit or personal uses, or against freeware developers who created GIF-making utilities. However, in September 1999, they issued a "clarification" that stated anyone using GIFs was subject to a patent infringement claim from Unisys if they used GIFs on any Internet or intranet site. You can imagine the furor that particular claim has caused. There’s a strong movement on the Web that advocates the abandonment of the GIF entirely in defiance of Unisys’s claims, but as we well know, GIFs are still the graphic of choice for many Web designers.

The Fate of the Humble GIF...

Where that leaves today’s GIF users is not completely clear. While legal opinion varies, most lawyers involved in the issue seriously doubt that GIF users, such as myself and SitePoint, are in any danger of breaking any patent law -- only the makers of graphics utilities that are capable of creating GIFs are responsible for any copyright or licensure fees. The best guess seems to be that if you’re using GIFs created by licensed programs (and most of the big boys like Paint Shop Pro, Illustrator, etc. have long since paid their fees to Unisys), you’re OK. If you maintain a personal or non-profit Website, you might technically be in violation, but Unisys isn’t going to bother you. However, if you’re using GIFs on your for-profit page, or you’re a software developer who markets a GIF creation program without a license from Unisys, you might get contacted one of these fine days.

Obviously this is NOT intended to be any kind of legal opinion or guideline; if in doubt, talk to a lawyer familiar with the issue, or contact Unisys at LZW_INFO@unisys.com

...and the Humble Web Designer

So do you need to worry if you’re a simple Web designer using GIF graphics? Well, as a Slashdot [5] poster said, "You cannot patent a sequence of numbers, you can only patent a process or algorithm for arriving at those numbers." Ultimately all GIF files are simply strings of numbers translated into pretty pictures by browsers and graphics programs, so it doesn’t seem feasible for Unisys to try to collect royalties or payments from the likes of us. Most smaller shareware creators, like Ian Timmins of My Web Toolbox [6] fame, stay away from the issue by refusing to support the GIF format in their programs. The state of affairs is illustrated well by Unisys spokesman Oliver Picher, who says:

Picher asserts that Unisys is not out searching for violators of its patent. He added that most programs producing GIFs are licensed, so there's usually no problem. The best advice for commercial users is for them to ensure that the GIFs they use are created by licensed graphics programs.

Another alternative is to use the newer PNG graphics format. PNG (officially Portable Network Graphics; unofficially Png is Not Gif or even Pretty Nifty Graphics) began as GIF24, a 24-bit graphics format developed by Compuserve and outside developers. PNG graphics do everything that GIFs do, except animation (the obscure MNG, or "Multi-Image Network Graphics" format handles animations), and do it better. Unfortunately, PNG graphics aren’t supported by most older browsers. The browsers that do support PNG include MSIE 5 and above, Netscape 4.x and above, Opera, and Mozilla, the open-source progenitor to Netscape 6. Refer to the PNG-Supporting Browsers [7] page for a list of all browsers that support PNGs in whole or in part.

As site developers have to take into consideration the use of older browsers by a significant part of their audience, many have chosen to avoid using PNGs. Others have put the format to use, and insist that their audience upgrade their browsers as needed. As for MNG files, they're not well supported. The format was finally given concrete specifications in January 2001 and is ready for use; unfortunately, none of the major browsers fully supports MNG as yet. Netscape 6 does support MNGs relatively well, but neither MSIE nor Opera supports the format at all. The Unix/KDE browser Konqueror supports MNGs, but the market share of Konqueror is quite small.

My guess is until Microsoft decides to support the MNG format in its browser, the usage of MNGs on the Web will be extremely limited at best. And Glenn Randers-Pehrson, one of MNG’s developers, doesn’t expect the MNG format to win the support of the major browsers anytime soon. "Based on how long it’s taken them to support PNG," he says, "I don’t have high hopes." ExtremeTech [8] recommends using Flash animation in place of MNG files.

PNGs are superior to GIFs in many ways. They are lossless graphics, which means that no image detail is destroyed. They compress better than either GIFs or JPGs, which means smaller file size and faster download times. And they support a much bigger color palette than GIFs, and also feature platform-independent gamma correction (which means they look pretty much the same on your PC as well as your neighbor’s Mac), multiple transparency layers as opposed to the single layer supported by GIFs, text area within the file for data (read copyright) storage, and more.

Currently a relatively small number of sites employ PNGs. Eventually they may well augment or even supplant GIF usage, but that day isn’t here yet. As more graphics designers turn to the PNG format, PNG graphics will become more and more common. Personally, I don’t foresee GIFs disappearing for the near future, especially as long as the mainstream graphics programs such as Paint Shop and Illustrator continue to support the format.

Bibliography

An Open Letter to All Web Cartoonists (proposal for Web ‘toons to go GIFless)
http://www.ubersoft.net/features/bothbarrels/20010316.html [9]

AspImage, LZW, and the Unisys Patent on GIF/LZW
http://www.serverobjects.com/lzw.html [10]

Burn All GIFs?
http://community.borland.com/devnews/article/1,1714,20002,00.html [11]

Burn All GIFs
http://burnallgifs.org/ [12]

C|Net: Web Building – Authoring and Site Design – Emerging Web Standards
http://builder.cnet.com/webbuilding/pages/Authoring/Standards/ss02.html [13]

Companies Licensed by Unisys
http://www.unisys.com/unisys/lzw/lzw-companies.asp [14]

The GIF Controversy: A Software Developer’s Perspective
http://cloanto.com/users/mcb/19950127giflzw.html [15]

Group 42: PNG Info
http://www.group42.com/png.htm [16]

LZW FAQ
http://www.cpe.surrey.ac.uk/support/faq/gif_lzw.htm [17]

MNG Home Site
http://www.libpng.org/pub/mng/ [18]

PNG Home Site
http://www.libpng.org/pub/png/ [19]

PNG-Supporting Browsers
http://graphicswiz.com/png/pngapbr.html [20]

Unisys Not Suing (Most) Webmasters for Using GIFs
http://slashdot.org/articles/99/08/31/0143246.shtml [21]

Web Clip Art Glossary
http://webclipart.about.com/library/glossary/blglossary.htm [22]

Web Sites License Info from Unisys
http://www.unisys.com/unisys/lzw/lzw-license.asp [23]

[1] http://www.webmasterbase.com/article/628
[2] http://www.compuserve.com
[3] http://www.unisys.com
[4] http://burnallgifs.org
[5] http://www.slashdot.org
[6] http://www.australianwineandbeer.com/mwt/toolbox.htm
[7] http://www.libpng.org/pub/png/pngapbr.html
[8] http://www.extremetech.com
[9] http://www.ubersoft.net/features/bothbarrels/20010316.html
[10] http://www.serverobjects.com/lzw.html
[11] http://community.borland.com/devnews/article/1,1714,20002,00.html
[12] http://burnallgifs.org/
[13] http://builder.cnet.com/webbuilding/pages/Authoring/Standards/ss02.html
[14] http://www.unisys.com/unisys/lzw/lzw-companies.asp
[15] http://cloanto.com/users/mcb/19950127giflzw.html
[16] http://www.group42.com/png.htm
[17] http://www.cpe.surrey.ac.uk/support/faq/gif_lzw.htm
[18] http://www.libpng.org/pub/mng/
[19]
[20] http://graphicswiz.com/png/pngapbr.html
[21] http://slashdot.org/articles/99/08/31/0143246.shtml
[22] http://webclipart.about.com/library/glossary/blglossary.htm
[23] http://www.unisys.com/unisys/lzw/lzw-license.asp