On June 20th, the patent on the GIF image format expired. If you remember, CompuServe has owned the pattent on this image file format and has required software developers to pay a licensing fee in order to give their applications the ability to save graphics in GIF format. Even PHP developers were bound by patent until now.
There is a patch circulating on the web that adds GIF functionality to the GD library for PHP. The patch doesn’t look easy to install, but the good news is that there is a rumour that the patch will be included in the next minor release of PHP.
You should be aware that the patent has expired in the US and a few other countries. In Canada, the patent expires on June 20th, 2004. If your site is hosted in the US, you should have no problem using the GIF format (disclaimer – I am not a Lawyer!)
