In file,
/customer/main/product.tpl
you'll see some code for detailed images, including:
Code:
{if $active_modules.Detailed_Product_Images && $config.Detailed_Product_Images.det_image_popup eq 'Y' && $images ne '' && $js_enabled eq 'Y'}
{include file="modules/Detailed_Product_Images/popup_image.tpl"}
{else}
...
This may be a starting place.
IF the detailed product images in on, and if there is a detailed product image, show the image, else....
WHERE do you want to show this image?