Creating JPEG, PNG, and WBMP Images
The majority of the image functions draw their functionality from the GD library, free software for manipulating images. These require the GD extension to be loaded, via php3.ini or the dl function. The four functions in the first section of this chapter are not part of the GD extension and should always be available to you.
The GD library was created at Boutell.com, a company that has contributed several Open Source tools to the Web community. The library historically supported GIF image creation, but in 1999 this functionality was pulled in favor of PNG format files. The compression algorithm used in GIF creation is patented, which means permission ...