ios 保存图片到相册

+ (UIImage *)snapshot:(UIView *)view size:(CGSize )size{
    UIGraphicsBeginImageContextWithOptions(size,YES,0);
    [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

//保存
- (void)saveImageToPhotos:(UIImage*)savedImage {
 UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}

- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo {
    NSString *msg = nil ;
    if(error != NULL){
        msg = @"保存图片失败" ;
    }else{
        msg = @"保存图片成功" ;
    }
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存图片结果提示" message:msg delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];
    [alert show];
}