code: public static RenderedImage toRenderedImage(Image img) {
  		if (img instanceof RenderedImage) {
  			return (RenderedImage) img;
  		}
  
  		return copyImage(img, BufferedImage.TYPE_INT_RGB);
  	}
docs: {@link Image} 转 {@link RenderedImage}<br>
  首先尝试强转，否则新建一个{@link BufferedImage}后重新绘制
  
  @param img {@link Image}
  @return {@link BufferedImage}
  @since 4.3.2