We don't have a built-in way in JFBConnect to do that. However, there's a few different ways to do it. If you simply use the [fb:login-button scope="user_photos"] tag, that will request the permission when a user clicks on it.. even if they are already logged in.
There's also a FB.ui Javascript call you can use to request permissions, but I don't recall it offhand.
Hope that helps, but if you need more info, just let us know!
Alex
Custom Login Button
