I think the following Adblock Plus filter rule would do the trick:
||facebook.com^$third-party ||facebook.com^$third-party||facebook.com^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||facebook.net^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||fbcdn.com^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
||fbcdn.net^$domain=~facebook.com|~facebook.net|~fbcdn.com|~fbcdn.net
The key is to allow FB's CDN when on FB, but to disallow it and everything else when not on FB.
I'm never on FB so this takes care of it nicely.