Try thinking of it as selling “Really Big Prints” on eBay. We have a bias toward big images, you know. The article is a little dated, but still has a lot of info for the beginning eBay photo seller.
Selling Photography on eBay: “Selling Your Photography
You may be a beginner, an advanced amateur, or a professional photographer. No matter what your level of experience, selling your photographs can make a lot of sense. For a pro, sales are your lifeblood, and new markets are always welcome. For amateurs, sales can be a way to buy new equipment, or a path to joining the ranks of the professionals. There are a many kinds of markets for good photographs, but we are going to tell you how to take advance of a unique market that is largely unknown among photographers, the online auction market.”