利用PHPqrcode类库生成带参数的二维码后将它和其他图片进行合成，但是需要调整二维码的大小，然后用PHP的图片处理函数将它放大了3倍，但是这时和其他图片合成后，二维码里面的参数不见了，扫码之后什么都没有，怎么解？

上代码

require 'phpqrcode/phpqrcode.php';

$data = 'http://'.$_SERVER['SERVER_NAME'].'/hoax.php/Index/result?openid='.I('get.openid');
$level = 'L';
$size = 6;
$file = './Public/hoax/qrcode/qrcode.png';
$qrcode = new QRcode();
$qrcode->png($data, $file, $level, $size);
// 重构二维码大小
$qrfile = imagecreatefromstring(file_get_contents($file));
$qr_percent = 3.2;
list($qr_width,$qr_height) = getimagesize($file);
$qr_new_width = $qr_width * $qr_percent;
$qr_new_height = $qr_height * $qr_percent;
$qr_src = imagecreatefrompng($file);
$qr_new = imagecreatetruecolor($qr_new_width, $qr_new_height);
imagecopyresized($qr_new, $qr_src, 0, 0, 0, 0, $qr_new_width, $qr_new_height, $qr_width, $qr_height);
$bgimg = imagecreatefromstring(file_get_contents('./Public/hoax/img/2.png'));
imagecopymerge($bgimg, $qr_new, 100, 300, 0, 0, imagesx($qr_new), imagesy($qr_new), 100);
header('Content-Type:image/jpeg');
imagejpeg($bgimg);
imagedestroy($bgimg);