Here's an example of how to utilize images in your scene. When rendering a building with large windows, all we need to do is set up a billboard image of a room, such as this one, behind the window. Someone on Flickr took the photo for me. Thankyou!
But what if you're making an animated flythrough and the camera passes by the window slowly? The image behind the window won't move right at all. The answer is to mock up a quick Photo-Match room. Have a go yourself!