Served images through PHP won't load in Shadowbox

I've been using shadowbox without issue on my sites without issue for a while now. I've created a PHP file to serve media content from a protected folder. Here is what is in the download.php:

<?php
$fullpath="/home/user/media/image1.jpg";
header("Content-Type: image/jpeg");
header('Content-Transfer-Encoding: binary');
header('Content-Disposition: inline; filename='.basename($filename));    
header("Content-Length: " . filesize($fullpath));
readfile($fullpath);
exit;
?>

This works well if I call it using an IMG tag or try and download the image. For example:

<img src="download.php?id=123" />

However, if I use shadowbox the browser darkens and I don't even get a loading animation and nothing displays.

<a href="download.php?id=358" rel="shadowbox[test]"><img src="download.php?id=358"/></a>

The image will display fine with the example above, but the shadowbox won't load when clicked.

Thanks in advance!

Solution

The problem—for your case—is, Shadowbox check for file extension before fetching the content. If you search inside shadowbox.js (try search for img.ext), you will find this somewhere:

img.ext=["bmp","gif","jpg","jpeg","png"];

So, you could try adding PHP to loosen it a bit and Shadowbox will happily grab your image:

img.ext=["bmp","gif","jpg","jpeg","png","php"];

Or, you could save your php file as jpg (sounds weird, no?) and force the server to process it as a php file. For example, if you use Apache and .htaccess is allowed, you could try creating .htaccess (or adding these line to existing .htaccess file) with:

<files download.jpg>
  ForceType application/x-httpd-php
</files>