A corporate patent threat accidentally created the PNG format
In late 1994, computing firm Unisys announced it would enforce its patent on the LZW compression algorithm powering GIF images, demanding royalties from commercial software developers. Outraged programmers rebelled, organizing an online protest called Burn All GIFs Day and designing an open replacement from scratch in just months. The resulting format, PNG (Portable Network Graphics), introduced patent-free compression, 24-bit truecolor support, and 256 levels of alpha transparency.
The Patent Dispute That Shook the Early Web
In the early years of the World Wide Web, the Graphics Interchange Format (GIF) was the undisputed standard for digital imagery. Developed by CompuServe in 1987, GIF relied on the Lempel-Ziv-Welch (LZW) data compression algorithm to reduce image file sizes without sacrificing fidelity. Because LZW enabled efficient lossless compression on constrained storage and network bandwidth, GIF quickly became ubiquitous across bulletin boards and emerging web pages. However, software developers and users were largely unaware that the underlying LZW algorithm had been patented by the Unisys Corporation in 1983.
The situation changed dramatically in late December 1994, when CompuServe and Unisys announced a joint licensing agreement. Unisys declared its intention to enforce its patent rights, requiring commercial software developers creating GIF-capable tools to pay royalties. The announcement caused widespread panic and anger across the developer community, which viewed the sudden monetization of an essential web standard as an existential threat to open digital communication. Programmers realized that relying on proprietary, encumbered algorithms posed a systemic risk to the open web.
The backlash quickly catalyzed a unified response. The League for Programming Freedom and independent developer communities argued against software patents and organized public pushbacks, including the later symbolic campaign known as Burn All GIFs Day in 1999. More immediately, the crisis demonstrated that the internet needed an entirely new, unencumbered image format that could serve as a direct, technically superior replacement for GIF.