This is a funny trick. I would not refuse that Facebook is programmed to protect the privacy of their users to maximum extent. Update: Nowadays FB allows the users to view the full size picture of all users without any restriction.
Still there are some small loop holes like this .
Well, You can click the profile picture of your friend to see the enlarged profile picture.
Some users set their profile picture as public. So , we can get no issue on viewing those profile pictures in large size.
Now, let us think about those who set their profile pictures should not be viewed by public in large size.
Go to their profile page. Right click on the small picture and select open image in new tab.
Look the address bar very closely. There will be a lengthy address line. Inside that you can find a code /s320x320 or /s160x160
Just remove that code I typed in bold and press Enter.
Hurray, the picture grows to its maximum largest possible size.
I am sure, Facebook will fix it soon in the future. But until then we can enjoy this funny trick. Share this fun with your friends also by hitting f button below.