//On navigates to, set mainPage equal to passed in value
        //Check if front image or side image, set grid background
        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            mainPage = (FaceImagesPage)e.Parameter;
            if (mainPage.FaceMode == "Front")
            {
                mainGridImageBrush.ImageSource = mainPage.getFrontImage();
            }

            else
            {
                mainGridImageBrush.ImageSource = mainPage.getSideImage();
            }
        }
 //Sets main page
 protected override void OnNavigatedTo(NavigationEventArgs e)
 {
     mainPage = (FaceImagesPage)e.Parameter;
 }