As some of you may know I run a small picture hosting site. A user emailed me the other day to say that Internet Explorer was only allowing her to download images at BMP images, despite the image being a JPG or a GIF. Turns out this is a known issue. I figured that had to be a way to turn off caching via the HTTP headers and I think I have a solution. If you’re sending dynamic files via PHP give these headers a try.

<?php

// Your file's extension
$ext = 'jpg';

// Your file's name
$name = 'goofypicture.jpg';

// Your file's location
$src = '/path/to/'.$name;

header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false);
header("Content-Type: image/".$ext);
header('Content-Disposition: inline; filename="'.$name.'"');
header("Content-Length: ".filesize($src));

?>