Sorry to keep posting -- hoping someone jumps in on this...
I was not able to get the detailed images (colorbox) working.
I tried editing these files, using the smarty 'replace' command as used elsewhere:
/common_files/modules/Detailed_Product_Images/product_images.tpl
/common_files/modules/Detailed_Product_Images/colorbox_image.tpl
/common_files/modules/Detailed_Product_Images/popup_image.tpl
and replaced
{$i.image_url|amp}
with
Code:
{$i.image_url|amp|replace:'www.domain.com':'cdn.domain.com'}
...and that was a big old fail. The images are not served from the cdn. Hmm...
Maybe this needs a php solution after all?