说明：  将保存有灰度图像信息的txt文件转化生成灰度图片。 txt数据只能包含数据，数据用逗号或者空格隔开，所存数据个数应与所生成的图片大小相同。例：要还原的图片大小为640*480，那么txt文件中就应当有307200个数据。
(The txt file with information of grayscale image is transformed into gray image. The TXT data can only contain data, separated by commas or spaces, and the number of data stored should be the same as the size of the generated image. Example: the size of the image to restore is 640*480, so there should be 307200 data in the txt file.)