Another option would be something like this:
UIImageView *backgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Flow-02"]];
backgroundImage.contentMode = UIViewContentModeScaleToFill;
backgroundImage.frame = self.view.bounds;
backgroundImage.autoResizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
[self.view addSubview:backgroundImage];
[self.view sendSubviewToBack:backgroundImage];
Keep in mind that either approach is only a good idea of the image looks OK when scaled as needed.