Just got a email from picadmedia.com/ sounds interesting, but I dont know the company, they place ads on images.
it does sound interesting, and pretty new. you could be on to something, give it a try and let us know how you do.
I just got an email last night and I am trying them on a couple of my web sites now, I will report back here if I remember. You can always pm me a week from this post to find out how I am doing with the program.