/**
  * Unlink all cached images (i.e. temporary images either downloaded
  * or converted)
  */
 static function clear()
 {
     if (empty(self::$_cache) || DEBUGKEEPTEMP) {
         return;
     }
     foreach (self::$_cache as $file) {
         if (DEBUGPNG) {
             print "[clear unlink {$file}]";
         }
         unlink($file);
     }
     self::$_cache = array();
 }
  /**
   * Unlink all cached images (i.e. temporary images either downloaded
   * or converted)
   */
  static function clear() {
    if ( empty(self::$_cache) || DEBUGKEEPTEMP ) return;

    foreach ( self::$_cache as $file ) {
      if (DEBUGPNG) print "[clear unlink $file]";
      unlink($file);
    }

    self::$_cache = array();
  }