functiion for flipping images

function flipImage($image, $vertical, $horizontal) {
$w = imagesx($image);
$h = imagesy($image);

if (!$vertical && !$horizontal) return $image;

$flipped = imagecreatetruecolor($w, $h);

if ($vertical) {
for ($y=0; $y<$h; $y++) {
imagecopy($flipped, $image, 0, $y, 0, $h - $y - 1, $w, 1);
}
}

if ($horizontal) {
if ($vertical) {
$image = $flipped;
$flipped = imagecreatetruecolor($w, $h);
}

for ($x=0; $x<$w; $x++) {
imagecopy($flipped, $image, $x, 0, $w - $x - 1, 0, 1, $h);
}
}

return $flipped;
}