mod_rewrite image protection
function getImageFromOutside ( $homePath, $file )
{
    if ( file_exists ( $homePath . '/' . $file ) )
    {
        $contents = file_get_contents ( $homePath . '/' . $file );
        return $contents;
    }
}
$homePath = 'some_path/img';

if ( isset ( $_GET['uid'] ) )
{
    $img = $_GET['uid'] . '.jpeg';
    header ( 'Content-type: image/jpeg' );
    echo getImageFromOutside( $homePath, $img );
} else {
    print_r ( $_GET );
    echo file_exists ( $homePath . '/' . $file );
}

RewriteEngine On
RewriteCond   %{HTTP_REFERER}  !^$
RewriteCond   %{HTTP_REFERER}  !^http://www.yourdomain.com/.*$ [NC]
RewriteCond   %{HTTP_REFERER}  !^http://yourdomain.com/.*$     [NC]
RewriteRule   ^/PublicFiles/*$ /page-about-direct-links.html