I would take a look at other past auctions. When you're signed in, search for them, then select "Completed auctions" on the left side menu. You'll be able to see auctions for sold bags and find some that aren't stock photos but pictures taken by the actual sellers. See what they photographed. If they have a specific authenticity thing that needs to be taken photographed, make sure you post that. In the auction state that they are authentic and maybe say where you purchased them at even though I'm not sure if this is allowed on eBay but it never hurts to check.
As for the used bags with the lipstick stains, etc., make sure you write down the defects and photograph them so the buyers can see how bad it is. Chances are you wouldn't make as much for these as a normal used bag but something is better than nothing.
Good luck.