I was lookign for a hack like this, so I installed it, it did not do exacly what I needed so with a little hlp from Firefly and modifying the templates myself this is what I got
http://www.yaxay.com/yack/index.php
(check it out, it is worthed) .. look at the "Gallery"
It's hacked so the on/off images reflect the forum topic (when read the image shows grey)
LOVE IT