basic PHP image proxy (that works ... )

imageProxy.php

<?php

$url = isset($_GET['url']) ? $_GET['url'] : null;

if (!$url) {
    die('Please, inform URL');
}

$imgInfo = getimagesize( $url );

if ($imgInfo === false) {
    die('Could not retrieve information');
}

if (stripos($imgInfo['mime'], 'image/') === false) {
    die('Invalid image file');
}

header("Content-type: ".$imgInfo['mime']);
readfile( $url );

@carloscarucce right, that's much safer and exactly what I'm doing. :)