Avatar size change and signature BB code

[TerranoZergus]

Hello
I am really new, and have just (less than a month) installed my first Vbulletin at www.sc2forums.com. I am configuring it now, and can't find few basic things

a) I want nice big avatars, not small squares. Thing is, it will probably have to do with the user info shown with each post.
How do I change the size of the shown avatar ?

b) Where can I configure so [img] code is accepted in signatures ?


Thank you

Cheers

Help ?
Anyone ?
Just a simple question ? How to I adjust the avatar sizes ,and allow [img] code in the signatures ?