2003.gada 20.jūnijā beidzās US Patent 4,558,302 patents uz LZW kompresijas algoritmu, kas tiek izmantots GIF (Graphics Interchange Format) bildēs un 20 gadus piederēja kompānijai Unisys Corporation, kas par tā izmantošanu iekasēja autoratlīdzību.
LZW (Lempel Ziv Welch) algorithm is used to compress images in GIF (Graphics Interchange Format) files. Unisys Corporation patented this algorithm on 20th June 1983 and it expires after 20 years. In the early days of Internet this format released by CompuServe in 1987 became popular to store images. But Unisys decided in December 1994 that anyone who used the format needed a license. Big confusion and a lot of websites removed GIF files or changed them from GIF to JPEG.
Ieviestās maksas dēļ tika izveidots alternatīvs web-grafikas formāts PNG (Portable Network Graphics) kā arī anti-GIF kustība Burn All GIFs.