An inference is when you look at something, and basically guess what it is about/what the message is etc.
An inference to be made about this guy might be that he is an irresponsible parent, because his kid is about to put a fork into a toaster, while he is doing shots.
An inference to be made about these people is that they are professional dancers, because they are on a fancy stage. And dancing. So professional.
An inference to be made about this is that the ones with the horns are probably drunk. Why else would someone wear things like that?(I would it looks really fun)