How a dispute over royalties gave birth to the PNG file format
In late 1994, controversy was brewing over royalties being imposed on GIFs due to the Lempel–Ziv–Welch (LZW) data compression technique used to underpin this image format.
Unisys, which had patented the technique some years prior, insisted that royalties be imposed, which sparked a fierce backlash among developers.
The resulting battle led to the creation of the royalty-free Portable Network Graphics (PNG) format, which is still widely used today.
So how did it get to that point? In 1987, GIFs, an abbreviation for Graphics Interchange Format, were first released by CompuServe. When Unisys sought retrospective royalties over the use of LZW, a working group was established to begin development of an alternative.
Development on this front was led by Thomas Boutell, and the working group initially chose ‘PING’ as the name, translating to “PING if not GIF”.
While this was later shortened to PNG, the wheels were very much turning by that point and development accelerated rapidly. Long-running issues associated with GIFs, such as its lack of 24-bit color support, were highlighted as key development priorities.
By 1996, the full specification of PNG was finalized following the approval of the World Wide Web Consortium (W3C).
The benefits of PNGs
PNG files still remain highly popular in 2025 alongside the JPEG format. In fact, these two formats have a lot of overlap, but differ in where they’re used.
Both, for example, can handle 16 million colors. Notably, PNGs are typically used for web graphics, charts, illustrations, or logos, as opposed to high-quality photographs.
They also take up more space than your average JPEG. This is because they utilize “lossless compression”, which Adobe explains means that no data is lost when the image is compressed.
“The quality stays the same no matter how many times you edit and save the file,” the graphic design giant noted. “The image won’t become blurry or distorted, making PNGs ideal for sharp logos and graphs containing lots of figures”.
By contrast, JPEGs are designed specifically for efficiency, drawing upon a “lossy compression” technique. This means that some data is deleted when it’s altered or made smaller.
Still going strong
Despite their age, PNG images are still going strong. Support for this image format first appeared in 1997 on Internet Explorer and in NetScape.
Support for the format was also strong during this period, with the Unisys debacle having left a sour taste in many mouths. The Free Software Foundation and W3C were strong proponents of PNG images, and campaigns including ‘Burn All GIFs’ sought to stir up support.
Adoption rates were slow, however. A key factor behind this was a lack of support in Internet Explorer during the early days. As the PNG format includes support for transparency, this proved troublesome and buggy.
Regardless, PNG still ranks among the most widely-used image file formats on the web, with the majority of major browsers all offering support.
This includes Safari, Google Chrome, Firefox, Opera, and Microsoft Edge.
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In late 1994, controversy was brewing over royalties being imposed on GIFs due to the Lempel–Ziv–Welch (LZW) data compression technique used to underpin this image format. Unisys, which had patented the technique some years prior, insisted that royalties be imposed, which sparked a fierce backlash among developers. The resulting battle…
