     weak var layoutImageLeft:NSLayoutConstraint!
     let maxHeight:CGFloat
     let kMinHeight:CGFloat = 5
-    private let kMaxHeightPercent:CGFloat = 0.7
+    private let kMaxHeightPercent:CGFloat = 0.8
     private let kBorderHeight:CGFloat = 1
     private let kAnimationDuration:NSTimeInterval = 0.3
     

        NSNotificationCenter.defaultCenter().removeObserver(self)
    }
    
    //MARK: notified
    
    func notifiedDisplayOptionChanged(sender notification:NSNotification)

        imageView.contentMode = controller.model.displayOption.contentMode
    }
    
    private func layoutImage()
    {
        if imageView.image == nil
        {
            layoutHeight.constant = kMinHeight
        }
        else
        {
            let screenSize:CGSize = UIScreen.mainScreen().bounds.size
            let screenWidth:CGFloat = screenSize.width
            let screenHeight:CGFloat = screenSize.height
            
            if screenWidth < screenHeight
            {
                layoutHeight.constant = maxHeight
            }
            else
            {
                layoutHeight.constant = kMinHeight
            }
        }
        
        UIView.animateWithDuration(kAnimationDuration)
        { [weak self] in
                
            self?.layoutIfNeeded()
        }
    }
    
    //MARK: public
    
    func displayImage(image:UIImage?)
    {
        imageView.image = image
        controller.viewChat.input.updateStandbyMenu()
        layoutImage()
    }
    
    func removeImage()
    {
        imageView.image = nil
        controller.viewChat.input.updateStandbyMenu()
        layoutImage()
    }
}