To me, the sigpic does not seem to be a child. It's not even trying to kid us that it's a child.
However, under Canadian law, if the actor appears to be under-age, it is no defence to prove that the actor is actually a grown-up.
Who decides how old the actor appears to be? Of course, the judge hearing the case, if it comes to that. Given that this actor seems to be under-age to some terbites, if not to others, if I were Fuck-Face I'd be afraid.
I guess I'm pleased that his sigpic is not subject to legal sanctions for being despicably crude and tasteless. We just have to regard Fuck-Face as the price we pay for freedom of speech, on that score.