images doesn't seem to cache

Hi, I put all my images outside the web root, the prevent direct access, and then access them with a <img>-tag like this: <img src="fnc_get_image.php?path=<?=$path;?>" /> where fnc_get_image.php is: // Check if user is logged in require_once 'global_includes.php'; $user =& new User(); // Get path to image for display $path = $_GET['path']; // Prepend path - prevents misuse $pPath = "/home/username/albums/" . $path; header("Cache-Control: private"); $extention = substr($path, -3); if ($extention == "jpg")

    header("Content-type: image/jpeg");

if ($extention == "gif")

    header("Content-type: image/gif");

if ($extention == "bmp")

    header("Content-type: image/bmp");

if ($extention == "png")

    header("Content-type: image/png");

readfile("$pPath"); There is one slight problem though: To my eyes, it looks like the images are downloaded from the server every time. Is this a side effect of this method or is it just a optical illusion? Is there a way to tell for sure if the image is downloaded or displayed from the browser cache? I've tried with and without a Cache-Control header. It doesn't seem to do any difference at all. Best regards, Anders