网上找了资料不太全,刚好还有些时间就整理了一下,我也是抄的,已下是我做过可行,分享出来,
废口烂舌表达不出其中的奥义,上代码.......

#import "AboutWeiXinViewController.h"

@interface AboutWeiXinViewController ()

@property(nonatomic,strong)UIImageView *img;

@end

@implementation AboutWeiXinViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"我们的微信";
    self.view.backgroundColor = [UIColor whiteColor];
    
    //1.创建长按手势
    UILongPressGestureRecognizer *longTap = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(imglongTapClick:)];
    
    //2.开启人机交互
    self.img.userInteractionEnabled = YES;
    
    //3.添加手势
    [self.img addGestureRecognizer:longTap];
  
}

#pragma mark 长按手势弹出警告视图确认
-(void)imglongTapClick:(UILongPressGestureRecognizer*)gesture
{
    if(gesture.state==UIGestureRecognizerStateBegan)
    {
        UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"保存图片" message:nil preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
            NSLog(@"取消保存图片");
        }];
        
        UIAlertAction *confirm = [UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
            NSLog(@"确认保存图片");
            
            // 保存图片到相册
            UIImageWriteToSavedPhotosAlbum(self.img.image,self,@selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:),nil); }];
        
        [alertControl addAction:cancel];
        [alertControl addAction:confirm];
        [self presentViewController:alertControl animated:YES completion:nil];
    }
    
}

#pragma mark 保存图片后的回调
- (void)imageSavedToPhotosAlbum:(UIImage*)image didFinishSavingWithError:  (NSError*)error contextInfo:(id)contextInfo
{
    NSString*message =@"提示";
    if(!error) {
        message =@"成功保存到相册";
        UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {  }];
        
        [alertControl addAction:action];
        
        [self presentViewController:alertControl animated:YES completion:nil];
        
    }else
        
    {
        message = [error description];

        UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {   }];
        
        [alertControl addAction:action];
        
        [self presentViewController:alertControl animated:YES completion:nil];
        
    }
    
}

-(UIImageView *)img{
    if (!_img) {
        _img = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"weixinerweima"]];
    }
    return _img;
}


@end

这个时候我觉得可以了,但是结果是运行闪退
控制台报错信息:
This app has crashed because it attempted to access privacy-sensitive data without a usage description. The app's Info.plist must contain an NSPhotoLibraryAddUsageDescription key with a string value explaining to the user how the app uses this data.

原来iOS 10 保存图片、调用相机一样， Info.plist 里面要涉及隐私数据时要添加一句“提示语”

7B83EEA4-37B6-419A-BD9C-58279B6D99C1.png

在 Key 中输入：Privacy - Photo Library Additions Usage Description