code: public ImageElement addSecondaryImage(String src) {
          if (src == null) {
              throw new RuntimeException("Cannot set secondary image to null.");
          }
          ImageElement img = Document.get().createImageElement();
          img.setAttribute("src", src);
          getElement().appendChild(img);
          return img;
      }
docs: Adds secondary image to this list item. It's forcefully added directly to &lt;li&gt; element.
  <br> Additional CSS is needed to control appearance of this image, for example right side
  icon on the static band can be implemented, see <b>jqm4gwt-list-static-item-img-right</b> CSS rule.