That's another spam post I'm saving for posterity. You inspire the bots, kellis :3
Oh, to answer the question (how'd I miss this the first time?), pictures are turned off to make moderation easier (e.g. nobody, including the tiny number of bots which still escape our net, can post dirty stuff). So long as it isn't fully-pirated material (like no linking to unauthorized YouTube videos of full anime episodes or w/e) or isn't otherwise illegal in the States (no videos calling for violent death to America, thanks) we've no problem with linked videos.
And yes, people can make videos of our games as they wish. :V