There is an easy way to display Facebook Profile Picture if you already know their Facebook ID or Username. By using Facebook Graph API, you can get your own/anyone profile picture in 2 type of sizes: default(small) and large.
This method is public so you or your users aren’t be required to allow app permission or anything. And you can load any Facebook profile picture you want as long as you know their Facebook ID or Facebook username. Note that not all Facebook users register their username therefore using Facebook ID is better.
1. Display Facebook Profile Picture of User
In order to load Profile Picture of a particular Facebook user, simply access the picture from a URL below and as I mentioned above, we can display it in 2 difference sizes: small and large.
Using Facebook ID or Username will return the same result and just replace my username(hoanhuynhtrong) or ID(1258565465) with the username or ID you want to display their profile picture.
2. Save Profile Picture to file
<?php $fid = "hoanhuynhtrong"; $img = file_get_contents("https://graph.facebook.com/" . $fid . "/picture?type=large"); $file = dirname(__file__). "/" . $fid . ".jpg"; file_put_contents($file, $img); ?>