PHP. Руководство по PHP. 2005
imagecolorset
imagecolorset
Description
void imagecolorset (resource image, int index, int red, int green, int blue)This sets the specified index in the palette to the specified color. This is useful for creating flood-fill-like effects in palleted images without the overhead of performing the actual flood-fill.
See also imagecolorat().
imagecolorresolvealpha
imagecolorsforindex