public void drawImageCentred(Graphics g, Image image) {
    if (element != null) {
      Graphics2D g2 = (Graphics2D) g;
      Rectangle r = element.jGetBounds();

      int mitteX = r.width / 2;
      int mitteY = r.height / 2;
      int imageMitteX = image.getWidth(null) / 2;
      int imageMitteY = image.getHeight(null) / 2;

      g2.drawImage(image, r.x + mitteX - imageMitteX, r.y + mitteY - imageMitteY, null);
    }
  }
 public void onDispose() {
   if (image != null) {
     image.flush();
     image = null;
   }
 }