(PHP 3 >= 3.0.6, PHP 4, PHP 5)
The imagecolordeallocate() function de-allocates a color previously allocated with imagecolorallocate() or imagecolorallocatealpha().
<?php $white = imagecolorallocate($im, 255, 255, 255); imagecolordeallocate($im, $white); ?>
See also imagecolorallocate() and imagecolorallocatealpha().