code: private BufferedImage getImage(int layer) {
  		BufferedImage image = layeredImage[layer];
  		if (image == null) {
  			createImageAndGraphics(layer);
  			image = layeredImage[layer];
  		}
  		return image;
  	}
docs: Get the bitmap for the layer index
  
  @param layer
  layer index
  @return bitmap