private void SetSessionBackground (UINavigationBar navigationBar) { var version = Convert.ToDecimal (UIDevice.CurrentDevice.SystemVersion.Split ('.').First ()); if (version >= 7) { navigationBar.SetBackgroundImage (UIImage.FromFile ("images/SessionsHeader3.png"), UIBarMetrics.Default); } else if (version >= 5) { navigationBar.SetBackgroundImage (UIImage.FromFile ("images/SessionsHeader2.png"), UIBarMetrics.Default); } else { navigationBar.InsertSubview (new UIImageView (UIImage.FromFile ("images/SessionsHeader2.png")), 0); } }