was there any indication of why it should be 400 pixels deep as well as wide?

from a usability point of view it just puts everything "below the fold" (below what is visible in the browser without scrolling) and causes extra scrolling every time someone wants to access the thread...something that bugged the h*ll out of me evey time i wanted to access the spectator's gallery thread.

400 x 400 is a huge image, affecting load time as well as screen real estate. unless jot gave a specific reason for this kind of depth, or the square format, (perhaps he just stated the maximun allowable size), i vote for a horizontal banner that loads faster and does not take up the entire page.