This function will allow you to use '#ABCDEF' or '0xEEFF33' instead of the RGB values required for imagecolorallocate() by stripping away any non hex characters. It will also check and make sure that it's a valid 6 digit hex value after the stripping of non-hex characters takes place.

it simply uses the function hexdec() to convert each R, G, and B hex values to decimal, and then passes them to imagecolorallocate() individually.

See the page: http://us3.php.net/imagecolorallocate
to learn how to use this wrapper function.