Hello All!
     I have never used image layers, which I guess is a throwback from iClone 4, but I recently just went into it, dragged in a png as the diffuse, made a quick opac and dragged that in as well.  Evidently there is more to it, as the window did not become "cut out" to reveal the scene underneath, as I had hoped it would.  Is there a bunch of layer stuff that has to be done in paint.net?  I never use layers, so I am pretty clueless.