把图片保存到相册

- (void)save
{
    // 将图片写入相册
    UIImageWriteToSavedPhotosAlbum(self.imageView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    if (error) {
        NSLog(@"保存失败!");
    } else {
        NSLog(@"保存成功!");
    }
}