That said, you can't filter everything they send you, because some of it might be important. Here's a way to selectively filter messages from people you know in such a way that generally only spam gets diverted to a folder for review later.
If you're using Outlook, this is pretty easy to do. The trick is that you want to create a rule that checks for two things: Only the recipients who send you a lot of junk mail, and the presence of a FW: in the subject line (which is the dead giveaway for pictures of kittens with melon helmets, rambling conspiracy theories, and motivational poems about the power of hope).
You don't want to filter all forwards, because an awful lot of business e-mail comes that way. And you don't want to filter every mail you get from these people, because some of it might not be pointless forwards.
Your rules dialog should look like this:
When you put this filter into action, you should see a relaxing drop in the volume of Friend Spam arriving in your inbox.