color of AdSense image ads?

I've often wondered if AdSense chose different image ads to deliver based on the color pallettes you chose for the text ads... that is, if you chose a predominantly black pallette, would they deliver advertisements with black backgrounds? Anyone know?

 

I cant see this being correct myself but I honestly dont know.

 

I personally think it's due to the keyword that Advertisers are bidding for that their ads get shown rather than based on colour. I think Google works towards the Advertiser and that the highest bidder gets the best/top ad slot for that keyword. Just my thoughts.