             }, completion: {(finished: Bool) in
                 fromViewController.view.alpha = 1
                 transitionView.removeFromSuperview()
+                transitionBackgroundView.removeFromSuperview()
                 transitionContext.containerView()!.addSubview(toViewController.view)
                 transitionContext.completeTransition(true)
         })

            }, completion: {(finished: Bool) in
                self.referenceSlideshowView.alpha = 1
                transitionView.removeFromSuperview()
                transitionContext.completeTransition(true)
        })
    }

    func animateZoomInTransition(transitionContext: UIViewControllerContextTransitioning) {
        let fromViewController: UIViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!
        let toViewController: FullScreenSlideshowViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) as! FullScreenSlideshowViewController
        let transitionBackgroundView = UIView(frame: transitionContext.containerView()!.frame)
        transitionBackgroundView.backgroundColor = toViewController.backgroundColor
        transitionContext.containerView()!.addSubview(transitionBackgroundView)
        
        let transitionView: UIImageView = UIImageView(image: self.referenceSlideshowView.currentSlideshowItem!.imageView.image)
        transitionView.contentMode = UIViewContentMode.ScaleAspectFill
        transitionView.clipsToBounds = true
        transitionView.frame = transitionContext.containerView()!.convertRect(self.referenceSlideshowView.currentSlideshowItem!.bounds, fromView: self.referenceSlideshowView.currentSlideshowItem)
