I know you guys are out there trying to make a living, but the sites that make it so I can't even save a web-quality image piss me off into not wanting to buy anything (nothing against you, just a general rant - some photog has that and I cannot remember who).
I don't blame them, there are Photoshop plugins that enable users to upsize images (near loss-less) so people could print their high-res copies. I'm pleasantly surprised to see free downloadable images, so kudos to Happysnapper.
I buy some of the better pictures from John Weiland, I probably bought 10 or more prints from him last year, and 3 so far this year. I prefer buying from him trackside because he'll sometimes give a bundle price for several pictures, whereas most online purchases are fixed-price per print.
Happysnapper, I think a bundle package of several prints at a reduced price (as mentioned above) could be a positive differentiator for you. For example, $20 for a single 8x10 is fine, but 3 for $40 is much more attractive to me. Also, I'd like to be able to use the images I purchase on my website, even if I need to list a photo credit with the image.
Hope that feedback helps. Oh, and nice shot of me, thanks!