php透明合并png与jpg图片

<?php
$png = imagecreatefrompng('./mark.png');
$jpeg = imagecreatefromjpeg('./image.jpg');

list($width, $height) = getimagesize('./image.jpg');
list($newwidth, $newheight) = getimagesize('./mark.png');
$out = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($out, $jpeg, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
imagecopyresampled($out, $png, 0, 0, 0, 0, $newwidth, $newheight, $newwidth, $newheight);
imagejpeg($out, 'out.jpg', 100);
?>

另外一种方法：

$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);