Using Facebook graphics api is it possible and should I cache my profile picture?

I am using logon with facebook in my web app. Because of this, I will always have the user id of the current facebook user. I want to use a profile picture in my application, I can do it easily:

<img src="http://graph.facebook.com/<%- accountId %>/picture?width=200&height=200">

      

        
        
        
      

    

It seems fine if I just show the picture in the current users dashboard, but what if I want other users to see each other's photos? Is it a good idea to always link each user's images like above? In this case, it will be a replica of requests to facebook for each kind of my application. Or is it necessary to load each pic user profile when registering and displaying it from my database? Can I do it? In this case, how do I save the image to my mongoDB database via the waterline (sails.js)?