Installing/Configuring
PHP Manual

Requirements

If you have the GD library (available at » http://www.libgd.org/) you will also be able to create and manipulate images.

The format of images you are able to manipulate depend on the version of GD you install, and any other libraries GD might need to access those image formats. Versions of GD older than gd-1.6 support GIF format images, and do not support PNG, where versions greater than gd-1.6 and less than gd-2.0.28 support PNG, not GIF. GIF support was re-enabled in gd-2.0.28.

Note: As of PHP 5.4 libgd-2.1.0 or higher is required. Alternatively, use the bundled GD library that ships with PHP as of 4.3.

You may wish to enhance GD to handle more image formats.

Supported image formats
Image format Library to download Notes
gif   Only supported in GD versions older than gd-1.6 and newer than gd-2.0.28. Read-only 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.
jpeg » http://www.ijg.org/ When building the jpeg 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.
png » http://www.libpng.org/pub/png/libpng.html Only supported in GD versions greater than gd-1.6.
xpm » ftp://metalab.unc.edu/pub/Linux/libs/X/!INDEX.html It's likely you have this library already available, if your system has an installed X-Environment.

You may wish to enhance GD to deal with different fonts. The following font libraries are supported:

Supported font libraries
Font library Download Notes
FreeType 1.x » http://www.freetype.org/ This deprecated feature will certainly be removed in the future.
FreeType 2 » http://www.freetype.org/  
T1lib » ftp://sunsite.unc.edu/pub/Linux/libs/graphics/) Support for Postscript Type 1 fonts (Removed as of PHP 7.0.0).


Installing/Configuring
PHP Manual