Fine Art America is the world's most powerful sales and marketing tool for photographers and visual artists.
Simply open an account, upload your images, set your prices for all our available products, and you're instantly in business! FAA provides you with an e-commerce website, fulfills your orders for you, and sends you your profits each month.
It's not so much sizing as aspect ratio. All the thumbnails are cropped square, presumably to keep the pages looking neat and tidy. It can make some images look really weird, but we can't do anything about it.