/**
  * Set the stretch state for the image.
  *
  * @param newval The new state (true, if it should be stretched, false otherwise)
  */
 public synchronized void setStretch(final boolean newval) {
   if (symbolProperties != null) {
     symbolProperties.setStretch(newval);
   }
   getOnImage().setStretch(newval);
   getOffImage().setStretch(newval);
   repaint();
 }