Yeah, that's not what I meant to imply. Let's see if I can clarify this:
In this screenshot, the virus is the file loaded into the 2x2 IFRAME (at the bottom of the red area) within the 1x1 IFRAME (above red area). Yes, that file is not the ad itself (good luck fitting a useful ad into a 1px square), but the code serving the virus comes (indirectly) from the same site serving the ad.
(As for cookies, yes, there are privacy concerns surrounding the way these ads use cookies, but that's actually not part of this process.)
You want a screenshot proving that the file I pointed out is a virus? Well, I hope
[this] is good enough!
(Thanks for the +watch, by the way.)