Are those ads on top of the page ok, I mean that image on the left, nothing wrong putting it next to adsense ad, right? http://www.bettforum.com/forum
Google usually has problems when publishers put 4 small images directly besides the Adsense ads to make it seem like the images are part of the ads. One big ad like this won't give you any problems.
I'd go one step farther and add to the image tag: <img style="border: 1px solid #000000;" replacing the 000000 with whatever the color code is for that color green.