"Should we formally disallow merely illustrative pictures for they can
put us in very hot copyright waters or have some requirements as to
No, we do not need yet another policy; not to apply going forward, not to have people chasing back through the archives looking for violations.
No, we do not need a "bright line." ...
Going to echo doppelgreener here:
It's not necessary for us to police copyright law to this degree. In this instance you're even policing Blizzard's copyright harder than Blizzard itself does.
Clips of TV shows, movies, and so on are extremely common on the internet. Seeing as it is effectively free advertising, copyright holders seem to be pretty okay ...