if (!empty($PHPTHUMB_DEFAULTS) && is_array($PHPTHUMB_DEFAULTS)) {
    $phpThumb->DebugMessage('setting $PHPTHUMB_DEFAULTS[' . implode(';', array_keys($PHPTHUMB_DEFAULTS)) . ']', __FILE__, __LINE__);
    foreach ($PHPTHUMB_DEFAULTS as $key => $value) {
        if (!$PHPTHUMB_DEFAULTS_GETSTRINGOVERRIDE
            || !isset($_GET[$key])) { // set parameter to default value if config is set to allow _GET to override default, OR if no value is passed via _GET for this parameter