Mark,
Very nice. Need to offer larger sizes and also bump up your pricing. Should start closer to $30 for the smallest and then go up. Looking at the "green box" size, it looks like you can offer up to 40" prints or so. Usually when you to to the "Behind the Scenes" and fill out the info, the sizes that the file is,will show up and you can put prices up to that size.
Welcome and good luck!
Rich