Overlay Image Within Coordinates

Hey all,

I recently have a project which invovles attempting to automatically "mock-up" images with a standard logo.  For example, I have 1000 images of products, and I have one logo image that needs to be placed (over-layed) on top of each image.  I know I can do this with ColdFusion's imageOverLay() function.  However, I assume this always puts the overlayed image right in the middle of the underlying image (assuming they have the same width and height parameters).  I was wondering if there was any way possible to specify and X/Y coordinate of the top-left corner of the overlaying image, and have the overlayed image placed in that location?

An example of a site:

http://www.internalsearch.expandedproductsearch.com/catalog/48/

You'll notice that all of the products have an image properly placed on the products.  And I can assure you this wasn't done by hand.  They must have a way to specifying where the overlaying image should go for each product, and then it just automatically puts the overlaying image (logo) in that spot.  Can anyone think of any other way to do this?

Any information would be greatly appreciated!