记住
// self.image = [UIImage imageFromUIView:_contentImageView];
// BOOL s = [UIImagePNGRepresentation(image) writeToFile:@"/Users/apple/Desktop/test.png" atomically:YES];
// NSLog(@"%d",s);
// image = [UIImage imageFromUIView:(UIView *)sender];
// self.image = [UIImage imageFromUIView:_contentImageView];
// BOOL s = [UIImagePNGRepresentation(image) writeToFile:@"/Users/apple/Desktop/test.png" atomically:YES];
// NSLog(@"%d",s);
// image = [UIImage imageFromUIView:(UIView *)sender];