Ask HN: Simple and Elegant Graphics App for Novices?

My day-distraction-project Profile Banner went viral a couple weeks ago (even though I got no love from HN!). http://www.facebook.com/apps/application.php?id=117320678334654

I'm getting 200k impressions per day, but I don't want to put skeezy ads all over the place to pay for the servers I need to buy (or lease or whatever).

I was thinking that I could sell a really simple graphics app. I get quite a few requests for recommendations. My users want something easy to make the banner of their dreams.

I sent Pixelmator (http://www.pixelmator.com) an inquirey (a few minutes ago), but I thought I'd ask here for recommendations. My users are young, international, and a little silly.

I'd love to find something that feels more like an iPhone app than a desktop one. I think $20 would be a good price point, hopefully with at least a $5 referral payout.

Any suggestions. I'd also be curious about open source ones (but REALLY simple), and other suggestions for monetizing. I am working on a system where users can pay to get their banners featured so they get more downloads. But who knows if that will work out.