Because of patent/copyright issues, GIF support has been removed from PHP. Once the patent expires worldwide on July 7th, 2004, GD will once again support GIF images.
There is a workaround to this. You can find the GD library with GIF support at http://www.rime.com.au/gd/
If you are worried about the legality of this, feel free to read up on it but I've read that the patent has expired in the US (making it legal in the US) and they are just waiting for it to expire worldwide before changing the PHP bundle.
The easiest way to add GD using the above link is to download and install the complete patched GD library first and then compile GD with that library, not the bundled one.
--with-gd=/path/to/patchedGD/install/
Good luck
