说明：  实现翻页,如果图片文件中有不是图片格式的他不会显示，我让它自动跳过去。还有当图片到达文件末尾，上下页按钮不能用并给出提示。改观了软件的外观，稍微美观了些
(The realization of page, if there is not a picture format image files in him will not be displayed, I let it jump past. And when the picture reaches the end of the file, the next page button can not be used and give tips. Changed the appearance of the software, a little bit more beautiful )