You are missing the point.
KKW has a set bandwidth cap. If we exceed this cap, we are offline for the remainder of the paid month. With the number of users of the forum, plus all the lurkers - all of whom download the avatars to their computer when they visit, the 5-10k difference begins to add up. The forums themselves use a fair chunk of our monthly bandwidth as is. I'm sure everyone would rather have 80x80 and a working site than 100x100 and a site offline for 7 days a month.
And besides, why change something that isnt broken?
The greatest delight is to mark one's enemy, prepare everything, avenge oneself thoroughly, and then go to sleep.