wordpress如何修改缩略图链接

if (has_post_thumbnail()) {
    $post_thumbnail_url = get_the_post_thumbnail_url();
    $img = ' . $class . ' src="' . $post_thumbnail_url . '" title="' . get_the_title() . '" alt="' . get_the_title() . '" />';
} else {
    $img = ' . $class . ' src="' . get_stylesheet_directory_uri() . '/assets/images/thumbnail.png" />' . "\n";
}    

在获取图片缩略图时src="' . $post_thumbnail_url . '
图片缩略图带有域名，例如：https://www.example.com/wp-content/uploads/.
我想把域名去掉，只保留/wp-content/uploads/.
请指点如何修改

最简单的，直接替换
$post_thumbnail_url = substr($post_thumbnail_url,23);
也可以
$arr = array("https://" => "","http://" => "", "www.example.com" => "");
$post_thumbnail_url = strtr($post_thumbnail_url,$arr);