vBulletin Mods

Hi, I'm trying to create a conditional so users can chose to load or not load images from other users in our forum.

I just created a new field in the users profile named "Thread images" were a user can choose between show or not show images. Now I need to go to the tag and put a conditional there to read this option, something inside the bb code for images like:

if "thread images=1" show image; else load "you_choose_to_not_show_images_from_users.gif"

I also don't know were to edit the [img] tag =(

Can this be done? How?

Thanks =)