Misbehaving proxy : differentiating jpegs

so i need to run my external resources through a very simple proxy shown below:

<?php
$url = $_GET['rsrc'];
header( "content-type:image/jpeg" );
echo readfile($url);
?>

it works for many jpegs.

for example here it is pulling something i grabbed off a google image serarch:

but for some reason, it doesn’t work for some jpegs. here’s another one i grabbed from google:

it’s not even recognizing the second as an image as an image…

are there different headers for different types of jpegs? do i need to differentiate?

[[EDIT]] with the image that does not load, firefox simply spits back the url i entered, but in IE, there’s an error message:

<br />
<b>Warning</b>: readfile(http://www.telegraph.co.uk/arts/graphics/2007/05/18/bfdecino400.jpg): failed to open stream: HTTP request failed! HTTP/1.0 403 Forbidden in <b>/home/0/c/9/8143/8143/public_html/v2/localProxyTest.php</b> on line <b>12</b><br />
is it possible that the specific server that houses the image denies the “readfile()” command from external domains? hmmmmmm…

anyone know about this domain?