Allow members to turn on/off the Lightbox feature

[oldford]

I'd like to give my members the option to turn on or off the lightbox feature for attachments.

Lynne was helpful in this thread suggesting to make a User Profile Field and use it in a plugin to toggle the option in AdminCP.

I just don't know how to do that. So if anyone could do this mod or point me in the direction of a tutorial that might help me do it myself that would be great.

Thanks!