Hello,
I have a photo business.  I have a background image that is 5x7 in both portrait and landscape.  I want to place a nearly centered 4x6 on to the applicable background.  This will happen in batches of 50-100 images at a time, so being able to do it over and over again without too many steps is important. I have figured out how to place an image on top of another, but then have to manually center it each time.  
Any help would be greatly appreciated