Here is the link I used as a reference for the PNG, TIF question Rhia474 had:

http://www.posersoftware.com/documentation/12/Poser_Reference_Manual/OtherApps/Exporting/Exporting_Images.htm

Notice they mention using PNG or TIF if you want to preserve the alpha channel. 

This is just my own personal render. It's been some time since I really used Poser before, so learning the ropes again! :-)

"You're trying to hack a scene in the window using a reflection node.  Since you're using SuperFly, you're better off setting the scene up with a real glass shader and a background billboard with your image attached.  This will properly show up in any file format from your render.  The purpose of the alpha channel saved in your .PNG is for compositing in a third-party program like Photoshop or GIMP where you insert a separate image in post-work."

This makes sense to me, I'll have to try it. The shop I'm using is the Victorian Gift Shop which comes with Poser. I pretty much kept things as they are, so the window glass is how it came, except as mentioned I disconnected the reflection node. It looks like they were using this to put snow on the windows(that's how it looks by default).

On a side note, there were around 42 lights in the Victorian Gift Shop scene! I'm down to 9 lights with no difference that I can see. I've never seen that many lights used before.

Thanks for your help everyone, really appreciate it!

[Tim]