Hi,
My tests indicate there will be blank spaces for any unused image slots. It was coded well in anticipation of that need.
Your coder actually set up the template with 3 rows of 3 images each (9 total). You can continue the pattern, but there may be minor adjustments needed to the layout to accomodate more rows. Probably best done with an HTML editor with a little more horsepower than Auctiva's template editor.
Danno