ken_b - 1:21 am on Dec 4, 2012 (gmt 0)
I have a couple of adblocks that appear on every other page a1 - a2 - a1 - a2 etc, these two blocks do approximately the same as far as earnings go.
Both have been text/image for the last couple of years.
I set one to image only today. I'll see how that goes.