如何使用php优化裁剪后的图像？

<?php
// 裁剪图像
$sourceImage = imagecreatefromjpeg('original.jpg');
$width = imagesx($sourceImage);
$height = imagesy($sourceImage);
$targetImage = imagecreatetruecolor(200, 200);
imagecopyresampled($targetImage, $sourceImage, 0, 0, 0, 0, 200, 200, $width, $height);

// 优化图像质量
$optimizedImage = imagecreatetruecolor(200, 200);
imagecopyresampled($optimizedImage, $targetImage, 0, 0, 0, 0, 200, 200, 200, 200);

// 压缩图像大小
imagejpeg($optimizedImage, 'optimized.jpg', 80); // 80为压缩质量参数

// 清理资源
imagedestroy($sourceImage);
imagedestroy($targetImage);
imagedestroy($optimizedImage);
?>