Please review my adsense layout and placement

I am working on the multimedia, wallpaper and illusions section. Can anyone give me some good advice on how i can get better results from this site. I don't want to get really far into it if i am doing something that isn't helping. Thank you.

http://www.alchemyimageworks.com/mmedia.html

 

i like the location but blen it change the background of the ad to gray