How do you block people from commenting on your cover photo on facebook?

[Ace]

I seen someone who is able to do it, I'm tired of having complete strangers liking and commenting on my cover photo. And I hate the fact you can't make it private

[Bob]

If your age is more than 18, people whose friend requests you ignore or hide automatically follow you.

If you want only your friends to comment on your cover photos, do the following:

Go to account settings and select Followers on the left tab.
Now click on Follower Comments and select Friends.

Also if you don't want followers you can turn it off.