function rex_image_ep_mediaupdated($params)
 {
     rex_thumbnail::deleteCache($params["filename"]);
 }
<?php

/**
 * Image-Resize Addon
 *
 * @author office[at]vscope[dot]at Wolfgang Hutteger
 * @author markus.staab[at]redaxo[dot]de Markus Staab
 * @author jan.kristinus[at]yakmara[dot]de Jan Kristinus
 *
 * @package redaxo4
 * @version $Id: index.inc.php,v 1.6 2008/03/20 18:13:13 kills Exp $
 */
require $REX['INCLUDE_PATH'] . '/layout/top.php';
if (isset($subpage) and $subpage == 'clear_cache') {
    $c = rex_thumbnail::deleteCache();
    $msg = 'Cache cleared - ' . $c . ' cachefiles removed';
}
// Build Subnavigation
$subpages = array(array('', 'Erkl&auml;rung'), array('settings', 'Konfiguration'), array('clear_cache', 'Resize Cache l&ouml;schen'));
rex_title('Image Resize', $subpages);
// Include Current Page
switch ($subpage) {
    case 'settings':
        break;
    default:
        if (isset($msg) and $msg != '') {
            echo rex_warning($msg);
        }
        $subpage = 'overview';
}
require $REX['INCLUDE_PATH'] . '/addons/image_resize/pages/' . $subpage . '.inc.php';