php通过修改header强制图片下载

$file_name = $imgUrl;//图片链接

$mime = 'application/force-download';

header('Pragma: public'); // required

header('Expires: 0'); // no cache

header('Cache-Control: must-revalidate, post-check=0, pre-check=0');

header('Cache-Control: private',false);

header('Content-Type: '.$mime);

header('Content-Disposition: attachment; filename=1.png');

header('Content-Transfer-Encoding: binary');

header('Connection: close');

readfile($file_name); // push it out

exit();