Skruntie - PM sent.
Right. Avatars. History. Site stability/capacity.
Firstly, the software upgrade. This HAD to be done quicker than we anticipated, thus only had 1 week of testing - mostly with ie7 and ff3, and mostly by me (which introduces a false sense to test due to my network connectivity). Reason it had to be done in a hurry was the forum was about to hit its capacity limit, and anyone with an ounce of intelligence could have DOS'd it. Remember, we have a few credible DOS threats from people capable, as well as a few from those incapable, not to mention another forum we severely pissed-off. So, the upgrade was hurried with insufficient testing. We were within days of pretty much losing the site.
Once upgraded, we had a massive problem with the new code, which meant we had to disable automatic image resizing - this is when the avatar issue came to light. The avatar sizes have always been in rules (mainly for low bandwidth users).
Now we have, until people resize, and issue - page jumping for ie users, or avatars sizes for ff users. in october, the ie:ff ratio for our site was 72%:19%, so guess which way we chose, and why

. Add 93% in october used windows, and all windows comes with ie, thats a simple workaround

, esp when there are very few reasons to use ff on windows technically (even if just temp whilst we resolve this issue).
I cannot dedicate 100% of my time to resolve this issue - I have worked closely with developers to get current workaround, and a full fix some be in next release. I do not have the time to test and deploy a cvs version at the moment.