如何优化PHP开发中的图片处理和图像操作

$allowed_types = array('image/jpeg', 'image/png', 'image/gif');
$file_info = getimagesize($_FILES['image']['tmp_name']);
if (!in_array($file_info['mime'], $allowed_types)) {
    echo "不支持的图片类型";
    exit;
}

$image = new Imagick('original.jpg');
$image->scaleImage(800, 600);
$image->writeImage('scaled.jpg');

$original_image = imagecreatefromjpeg('original.jpg');
$original_width = imagesx($original_image);
$original_height = imagesy($original_image);
$thumbnail_width = 200;
$thumbnail_height = 200;
$thumbnail_image = imagecreatetruecolor($thumbnail_width, $thumbnail_height);
imagecopyresampled($thumbnail_image, $original_image, 0, 0, 0, 0, $thumbnail_width, $thumbnail_height, $original_width, $original_height);
imagejpeg($thumbnail_image, 'thumbnail.jpg');
imagedestroy($original_image);
imagedestroy($thumbnail_image);

$image = new Imagick('original.jpg');
$watermark = new Imagick('watermark.png');
$image->compositeImage($watermark, Imagick::COMPOSITE_OVER, 10, 10);
$image->writeImage('watermarked.jpg');