I also run a PHPBB board, v3.02.
I've tried to figure out how to get the darn scroll bars to go away for attached images in posts.
For the life of me I can't figure it out.
It looks like the admins here have that problem solved, and it would be great to know how to resolve this on my board.
I have searched PHPBB's forum to no avail.
Thanks in advance for any help (my members at my site thank you as well)