code: protected Vector<BackgroundImage> loadBackgroundImages(NodeData style)
      {
          CSSProperty.BackgroundImage img = style.getProperty("background-image");
          if (img == CSSProperty.BackgroundImage.uri)
          {
              try {
                  Vector<BackgroundImage> bgimages = new Vector<BackgroundImage>(1);
                  TermURI urlstring = style.getValue(TermURI.class, "background-image");
                  URL url = DataURLHandler.createURL(urlstring.getBase(), urlstring.getValue());
                  CSSProperty.BackgroundPosition position = style.getProperty("background-position");
                  TermList positionValues = style.getValue(TermList.class, "background-position");
                  CSSProperty.BackgroundRepeat repeat = style.getProperty("background-repeat");
                  if (repeat == null) repeat = BackgroundRepeat.REPEAT;
                  CSSProperty.BackgroundAttachment attachment = style.getProperty("background-attachment");
                  if (attachment == null) attachment = BackgroundAttachment.SCROLL;
                  CSSProperty.BackgroundSize size = style.getProperty("background-size");
                  TermList sizeValues = null;
                  if (size == null) size = BackgroundSize.list_values;
                  else if (size == BackgroundSize.list_values) sizeValues = style.getValue(TermList.class, "background-size"); 
                  BackgroundImage bgimg = new BackgroundImage(this, url, position, positionValues, repeat, attachment, size, sizeValues);
                  bgimages.add(bgimg);
                  return bgimages;
              } catch (MalformedURLException e) {
                  log.warn(e.getMessage());
                  return null;
              }
          }
          else
              return null;
      }
docs: Loads background images from style. Considers their positions, repetition, etc. Currently, only a single background
  image is supported (CSS2).
  @param style the style containing the image specifiations
  @return a list of images