code: private boolean newSharedImage(String name, String sharedName) {
      boolean success = true;
      ImageDescriptor id = getSharedByName(sharedName);
  
      if (id == null) {
        id = ImageDescriptor.getMissingImageDescriptor();
        // id = getSharedByName(ISharedImages.IMG_OBJS_ERROR_TSK);
        success = false;
      }
  
      descMap.put(name, id);
      imageMap.put(name, id.createImage(true));
  
      return success;
    }
docs: Register an image from the workspace shared image pool. If the image
  resource does not exist or fails to load, a default "error" resource is
  supplied.
  
  @param name name of the image
  @param sharedName name of the shared image ({@link ISharedImages})
  @return whether the image has correctly been loaded