Thanks for all the advice.
Looks nice - but under the hood: hmm.
I assume it's just a PS page mockup for testing purposes, right? If so, disregard most or everything below, according to the facts.
Otherwise, having a hotspotted image is pretty much Jurassic technology these days, and your search engine profile will probably be lower than the Dead Sea. Not to mention inaccessible to anyone with sight problems - remember that us oldies (well, some of us) have lots of disposable income. The tab order is also not logical: try getting about with your keyboard to see what I mean.
If the above is double Dutch, you may need to find someone to help you with current techniques for constructing XHTML and CSS web pages that work across all platforms.
The payment method as it stands is clunky and doesn't look at all professional. You do need to integrate it on the sales page and give your purchasers a consistent experience, otherwise they may wonder who they are giving their money to. There are so many slick sites selling photos out there, and you do have to compete with them on all levels, however beautiful your photos are.