code: @Override
      public void link(NGScope scope, JQElement element, JSON attrs) {
          ImageResource resource = scope.get(getName());
          if (resource == null) {
              LOG.log(Level.WARNING, "Mandatory attribute " + getName() + " value is mssing");
              return;
          }
          Image image = new Image(resource);
          Element target = image.asWidget().getElement();
          String className = element.attr("class");
          target.addClassName(className);
          String style = element.attr("style");
          target.setAttribute("style", style);
          element.replaceWith(target);
      }
docs: Replaces the element body with the ImageResource passed via
  gwt-image-resource attribute.