Show Custom Selected User Profile Image on Postbit

[mcyates]

I run a football forum and i'm wondering how I can show the crest of their supported team so it shows in the postbit.

Basically It will be via Add New User Profile Field in the admin cp, but how would I achieve this?

I posted this in vbulletin and got half an answer from Lynne I just need to know how to make a plugin.
http://www.vbulletin.com/forum/showthread.php?347720-Show-Custom-Selected-User-Profile-Image-on-Postbit&p=1956746#post1956746

Thanks in advance.