We have the same problem from time to time athttp://cyphereal.net/forums and creating whitespace is our work-around too. However, it is hardly a fix. You are right, Monde, NewBB *should* take the current height of the picture into consideration.
I second the motion... I'm in the process of converting over a 1400 user, 45,000 post phpNuke/phpBB site to XOOPS and had given up on actual conversion.... If you have such a python script, I would dearly love a shot at it!