Hi Tina,
I cannot really rule out the possibility that there may be some issues transferring the template code your developers produces into our system but, if any such difficulties do arise, I think there is a good chance he/she will be able to work them out by making some changes to the template code.
In order to ensure that you can add images to listings for which you use this new custom template using the Auctiva uploader, you will just need to make sure that you (or your developer) incorporate the appropriate custom template tags into the template to indicate where the images you place in the Auctiva Image Selection section on the lister page should appear within the template.
Once you have pasted your custom template code into our custom template editor, which you can reach by mousing over the “Listings” tab within your account and selecting “Create New” under “Custom Templates”, you can will find the links that can be used to create these custom template tags on the left hand side of the page.
I hope this helps.
-Mike