If Auctiva Imported the listing info from an Active listing, the pictures should show in your Images library in the Imported Images folder. It might be one of the few exceptions to active pictures captured (once after direct listing) and synced back, so they can populate the Store and SG. I believe they only do the pictures once, so updating them at eBay after the fact requires manual change at Auctiva.
Now that's from my notes..... However, they are constantly making changes on both systems, and I keep getting surprises as a result.

Danno