Why charge per picture? Pictures = More likely to get sale, Less likely to disappoint the customer. I like the idea of making the initial listing of the item

Why charge per picture? Pictures = More likely to get sale, Less likely to disappoint the customer. I like the idea of making the initial listing of the item easy (although I'm still not sure on the benefits over just making an extremely simple, sell this form with 3 boxes (title, description, price). What is wrong with taking a small charge for the successful sale? The advantage of this is that everyone wins. The seller will only pay an amount (relatively small) when they have completed a sale and made money (and thus don't mind paying the small fees).