fileDownloadImage method
将本地路径的一个图片保存到相册 "/data/a/b/c/demo.png".fileDownloadImage()
Implementation
Future<dynamic> fileDownloadImage() async {
final file = io.File(this);
final imageBytes = await file.readAsBytes();
final result = await ImageGallerySaver.saveImage(imageBytes);
return result;
}