Hi Cameo Crafts,
In order to accomplish this when listing through Auctiva, you just need to specify your image grouping as "Thumbnails". Once you have selected your template, you will be taken to another pop-up screen entitled "Template Layout", and you should see the "Image Grouping" pull-down menu on the left-hand section of this screen.
Any additional questions or concerns? Please contact our customer support department using the appropriate link on our help page:
http://www.auctiva.com/free-auction-software-help/help.aspx-Mike