In general, marketing emails that are mostly images get binned by me. It's especially great when the only text is "unsubscribe" -- easy to find!
If the images really are important, and not easily replaced with text then I could understand your position easily.
I normally hate email with lots of images and prefer plain text over HTML, but in this particular case anyone claiming to read your emails with the images off is just trolling.
I am reminded of xkcd... http://xkcd.com/1172/
Actually, it would be better to change the frequency (slow them down) of your mailouts to that person with the option to request a return to the old frequency.
http://pandodaily.com/2012/03/06/facebook-knows-when-you-ope...
Our analytics wizards then use that and other data to come up with some estimates on how many users are opening our emails with images disabled.
I would consider it a bug if there was.