As we know that when we keep security for our profile picture we cannot view it in full size.
Now here is a trick which helps you to see the profile picture in full size even when the security is provided.
Follow the few simple steps give below:
Move your cursor to the profile picture and right click on it..select the option open the image in new tab
You will be getting some thing like this :
What you to do is..remove that s160x160 from the url.
This is what going to happen when you do that..
Now you can see the profile picture in full size .