code: public void render(OutputStream target, Graph graph) throws IOException {
  		
  		BufferedImage bi = 
  			new BufferedImage(graph.width, graph.height, 
  					GraphConfiguration.imageType);
  		Graphics2D g2d = bi.createGraphics();
  		graph.draw(g2d);
  	    ImageIO.write(bi, "png", target);
  	}
docs: Send a PNG format byte stream for the argument Graph to the provided
  OutputStream
  @param target OutputStream to write PNG format bytes
  @param graph Graph to send to the target
  @throws IOException for usual reasons.