Automatically add pages into document.

I have a application that I need help with.  Best way to explain this is the following:

Lets say I have a 200 page document.  I need to add a document onto the back side of the paper once it is printed.  I want to add a page (every other one) so that when I duplex print my paper, it will have the image on the back so I do not have to reload the paper a second time into my printer etc.  To better explain.....  If I start with a 200 page document, it will be 400 pages long where all the even numbered pages in the docusment will be the same image. 

ANY help would be greatly appreciated!!!

Thank you!!