Re-importing photo from facebook At the moment, the module fboauth imports the photo of the person from facebook and adds it as his/her profile picture, when configured to do so. Later on, when the person changes his/her profile picture, the photo will not be updated at the site because subsequent logins only imports fbuid.

How can the user re-import the photo (or any profile data for that matter) at a later point of time, and update it at the profile here? 

Please consider guiding me in the right direction and I will try to come up with some code. Will the hook fboauth_user_update() work for this? Or should I do the trouble of fetching, saving to server, and editing the db, etc? Please help.
its better to use Facebook realtime update https://developers.facebook.com/docs/graph-api/real-time-updates/v2.2

create your callback to handle this and register it with real time updates

do the following in your callback

1- load user from facebook ID you get it in the posted from facebook 

2- get the new image from facebook

3- replace it with the current image 

4- save user

or you can forget about real time update and replace the image whenever user login

here the code you can use 

1- Make your action by Implementing hook_fboauth_actions().

2- use hook_user_login to call the action you create which grab the photo and update it 

Thats all