I like to use a special graphic for the first photo and use pictures of the item itself for the other four. This way people who are clicking through your 'sold' items can see that you either did a bit of custom work (and what that work was - yay for the other four photos!) and/or that you're flexible and willing to work with your customer to cater a listing to them.
Here are a few 'Reserved' listing graphics for you to use. These are 1000 x 1000 pixels with a 72 resolution. Click the graphic for the full version and then right click to 'save as'.