     func refresh() -> Result {
         _thumbnailImage = nil
         _stereogramImage = nil
-        _leftImage = nil
-        _rightImage = nil
         return and(thumbnailImage().result, stereogramImage().result)
     }
     

        _propertyList = propertyList
        super.init()
        
        _leftImage = nil
        _rightImage = nil
        _thumbnailImage = nil
        _stereogramImage = nil
        

        if success {
            _thumbnailImage = nil
            _stereogramImage = nil
            return .Success()
        }
        return .Error(error!)
