code: private BufferedImage create_BACKGROUND_Image(final int WIDTH, BufferedImage image) {
          if (WIDTH <= 0) {
              return null;
          }
          if (image == null) {
              image = UTIL.createImage(WIDTH, WIDTH, Transparency.TRANSLUCENT);
          }
          final Graphics2D G2 = image.createGraphics();
          G2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  
          switch (getFrameType()) {
              case SQUARE:
                  BACKGROUND_FACTORY.createLinearBackground(WIDTH, WIDTH, getBackgroundColor(), getCustomBackground(), getModel().getTextureColor(), image);
                  break;
              case ROUND:
  
              default:
                  BACKGROUND_FACTORY.createRadialBackground(WIDTH, getBackgroundColor(), getCustomBackground(), getModel().getTextureColor(), image);
                  break;
          }
          G2.dispose();
  
          return image;
      }
docs: <editor-fold defaultstate="collapsed" desc="Image related">