hmmk not sure what you are experiencing either. When I have tried to edit imported listings, if you add images to the box you get double pics.
I would have the originals in the description and if I did not select images in the boxes - it would look fine but no gallery image. If I added images to the boxes, then I would get the original in the ad and also all the images at the bottom of the auction page.
Are you using Auctiva to crop the pictures? I do mine before bringing them here so that is an area I am not familiar with.