Only supported in GD versions older than gd-1.6 and newer than
GIF support is available with PHP 4.3.0 and the bundled
GD-library. Write support is available since
PHP 4.3.9 and PHP 5.0.1.
When buliding the jpeg-v6b library (prior to building PHP) you
must use the --enable-shared
option in the configure step. If you do not, you will receive
an error saying libjpeg.(a|so) not found
when you get to the configure step of building PHP.
Only supported in GD versions greater than gd-1.6.
It's likely you have this library already available, if your system
has an installed X-Environment.