The permissions on the gallery dirs of our 7.5 board occassionally get changed with the result that none of the images are viewable. Fixing it entails going in and resetting the perms to 777. Is there anything I can do that fixes this permanently so I don't have to fix it manually? Thanks!

I don't believe so (at the moment). But there is talk of this happening in the future. Take a look at the end of this thread.