Deleting a gallery photo is an example of something I would do in ebay after you relist. Ebay doesn't charge for changes unless you are adding features, I don't think you would be charged for deleting a feature.
The cut and paste process I mentioned is only to revise items in your template, or the template itself. ebay won't charge for these changes either.
So, to revise items outside the template use the ebay "revise your listing" page. If you revise these items in Auctiva (deleting gallery, for example) you would have to post the entire listing as a new listing, and thus lose your insertion fee refund.
Option: I've sometimes found it to be simpler to just make all my changes in Auctiva, post it as a new listing, and just forget about the insertion fee refund (it's not that much unless you have a lot of listings). Something to consider if it results in less hassle, more simplicity, and time saved. Either way works.