说明：  matlab在二值图像上画了一个红框，之后怎么把这个图像帮存下来（连红框一起保存），画框的方法用的是rectangle和drawnow两个函数
(matlab in the binary image on a red frame, then how to save this image (even with the red box to save), the box method is used rectangle and drawnow two functions)