private void GridScreenshots_ContainerContentChanging(ListViewBase sender, ContainerContentChangingEventArgs args)
{
args.Handled = true;
if (args.Phase != 0)
{
throw new Exception("Not in phase 0.");
}
StackPanel templateRoot = (StackPanel)args.ItemContainer.ContentTemplateRoot;
Image appIcon = (Image)templateRoot.FindName("appScreenshots");
appIcon.Opacity = 0;
args.RegisterUpdateCallback(ShowImages);
}