PHP学习-PHP输出图片下载

<?php
    $t=imagecreatetruecolor(100,100);
    $red=imagecolorallocate($t,255,0,0);
    imagefill($t,0,0,$red);
    header('Content-type:https://img.zuanmang.net/img/index.php');
    imagepng($t);
    imagedestroy($t);
?>