Thank you. This was EXACTLY what I was looking for and worked perfectly.
After following his steps to automate the desired images for both front and back, how did you go about getting them to print on both sides correctly?
Once you're on the PDF Presentation Screen, save it as a multi-page document. Tick "Add Open Files", and duplicate the page that you want to print double-sided and save it. It should save in your files. You should be able to open the PDF document and print it from there.