I don't see anywhere specific to address this, so I'll just throw out to the e-winds and see if someone answers.
I'd like to add BG to my links page, if that's agreeable.
Absolutely!
Is there a banner or image that is preferred (my allotted image size is 552x1000px)?
Thanks

JIT
I'm not aware of anything specific, but if you grab the banner image from the top left of this page (transparent PNG, 435x88) I'm sure that would be acceptable.