用subplot，imshow，imread，遍历并显示图库文件夹中的人脸图像（用循环）。运行后图像要显示成矩阵模式的，还得产生统一矩阵和均值矩阵。-With a subplot, imshow, imread, traverse and display the Gallery folder of face images (with circulation). After running into the matrix mode to display images, and have to produce unity matrix and the mean matrix.