If so, you add captions on the Images tab, Manage Images page for your images. You also need to select "Display Image Captions" box in the Image Selection section of the Auctiva one-page lister.
Note, captions are added at submission time on the listing and won't add or update to an active listing by later adding a caption to a stored image.
Danno
"Life is pain. Anyone who says differently isn't paying eBay and PayPal Seller fees."
No, the Auctiva captions are shown above the image on a listing. Here's one of my old Antiquarian book listings with thumbnail grouping and captions as an example. Note how the picture and caption changes as you pass mouse over thumbs. That grouping might work well for you too.