SO hex preview thing

<?php
header('Content-Type: image/png');
function rgbFromHex($hexValue) {

    //$hexValue = str_replace('#', '', $hexValue);
    //SILLY ME WAS EXPECTING # TO BE PASSED. BUT USING $_GET[] VARIABLES THAT ISN'T POSSIBLE... DAMMIT.

    if (strlen($hexValueValue) == 3) { //CHECK FOR SHORTHAND
        $r = hexdec(substr($hexValueValue, 0, 1) . substr($hexValue, 0, 1));
        $g = hexdec(substr($hexValue, 1, 1) . substr($hexValue, 1, 1));
        $b = hexdec(substr($hexValue, 2, 1) . substr($hexValue, 2, 1));
    } else { //FUNCTION FOR NORMAL 6 DIGIT VALUES
        $r = hexdec(substr($hexValue, 0, 2));
        $g = hexdec(substr($hexValue, 2, 2));
        $b = hexdec(substr($hexValue, 4, 2));
    }
    $rgb = array($r,$g,$b);

    return $rgb;
}

if ($_GET['color']) $col = rgbFromHex($_GET['color']); //DON'T DO ANYTHING IF A COLOR ISN'T PROVIDED
    $im = imagecreate(200, 40);
    imagecolorallocate($im, $col[0], $col[1], $col[2]); //FIND A BETTER WAY TO DO THIS.

imagepng($im);
//SWEET


?>