private async void ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     if (Model.CanDisplayPicture())
     {
         PictureViewModel viewModel = this.PictureList.SelectedItem as PictureViewModel;
         if (viewModel.OriginalImage == null)
         {
             await viewModel.LoadImageAsync();
         }
         this.Model.DisplayPicture     = viewModel;
         this.PictureList.SelectedItem = null;
     }
 }