PNG Was Drafted in a Week After Unisys Started Charging for GIF

On December 28, 1994, Unisys and CompuServe quietly announced that anyone writing software that produced GIFs would owe royalties on the LZW compression patent. The internet's most popular image format had been free for seven years; suddenly it wasn't.

A week later, on January 4, 1995, Thomas Boutell posted a draft to comp.graphics for a replacement. He called it PBF — Portable Bitmap Format. Two days after that, Oliver Fromme suggested PING, "PING is not GIF," and the name shortened to PNG. By the third week of January the format had alpha transparency, deflate compression, gamma correction, and a 24-bit color path that GIF never had.

This was unusually fast for a graphics standard. Most file formats are dragged through years of vendor committees. PNG had a deadline written by a patent letter: every commercial image tool was about to start owing Unisys money, and the Usenet thread wanted a clean alternative on the wire before anyone shipped a paid GIF encoder.

CompuServe — the very company that had originally cut the LZW deal — endorsed PNG as the "designated successor to GIF" on February 7, 1995, six weeks after the patent enforcement and before its own format had finished its public defense. The W3C made PNG a Recommendation on October 1, 1996. RFC 2083 followed in January 1997.

The patent that started it all expired in the United States on June 20, 2003. By then the lock-in had reversed. PNG was the default lossless format on the web, GIF survived only as a vehicle for animation, and the lesson — that a six-week panic on Usenet could outlast a corporate IP grab — was sitting in every browser's image decoder.