$dest = imagecreatefrompng('mapCanvas.png');
$src = imagecreatefromjpeg('si.jpg');
imagealphablending($dest, false);
imagesavealpha($dest, true);
// Copy and merge
imagecopymerge($dest, $src, 17, 13, 0, 0, 60, 100, 100);

// Output and free from memory
header('Content-Type: image/png');
imagepng($dest);

imagedestroy($dest);
imagedestroy($src);