Determine the dominant color of an image
This code will be super useful for people managing images or photography website. With it, you can analyze any image and get its dominant color (R, G, or B).

$i = imagecreatefromjpeg("image.jpg");

for ($x=0;$x<imagesx($i);$x++) {
    for ($y=0;$y<imagesy($i);$y++) {
        $rgb = imagecolorat($i,$x,$y);
        $r   = ($rgb >> 16) & 0xFF;
        $g   = ($rgb >>  & 0xFF;
        $b   = $rgb & 0xFF;

        $rTotal += $r;
        $gTotal += $g;
        $bTotal += $b;
        $total++;
    }
}

$rAverage = round($rTotal/$total);
$gAverage = round($gTotal/$total);
$bAverage = round($bTotal/$total);