The GD Library

   

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PHP provides the ability to create and manipulate images through support of the GD library. The GD home page is located at www.boutell.com/gd/ and lists the definition of GD as:

"An ANSI C library for the dynamic creation of images. GD creates PNG and JPEG images, among other formats. GD does not create GIF images."

Previously, GD was widely used for creating GIF images, but Unisys Corp., the company which owns the patent for the LZW compression algorithm used in GIF images, recently started enforcing their patent rights, and GIF creation was subsequently dropped from the list of GD features.

However, GD can still be used to create JPEG and PNG graphics, both of which are supported by most of the popular Web browsers. In addition, GD supports creation of WBMP images, which are used for small mobile wireless devices.

Basically, GD should cover your bases nicely for your scripted graphic creation needs. Note that GD is not a paint program. It can be used to manipulate existing images by adding text to them or to create new images out of two or more existing images.

GD is most useful in creating button images, as well as embedding captions in existing images.

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