I see, however it is not necessary to post such screen because that way you only ensure customers that you have items you are selling. I've seen many scammers posting images but when you meet them they try to kill you.
For all potential customers, I know AtomicWrangler a bit and I am pretty sure that he is a fair trader. Such recommendation is (in my oppinion) much more effective than a screenshot made by an auctioneer himself.