Lame_Wolf - 3:31 pm on Jun 12, 2012 (gmt 0)
Use jpgs for placement, and to give you an idea on how things lay.
Its hard to envision the ad coloring with a simple placeholder...no?
You can use photoshop (to a certain extent) to test colours. Or, wait till you have an account of your own, and try it that way like most people do.