Getting full-size profile picture

found a way:

$albums = $facebook->api('/' . $user_id . '/albums');
foreach($albums['data'] as $album){
    if ($album['name'] == "Profile Pictures"){
        $photos = $facebook->api('/' . $album['id'] . '/photos');
        $profile_pic = $photos['data'][0]['source'];
        break;
    }
}

As noted above, it appears that the cover photo of the profile album is a hi-res profile picture. I would check for the album type of "profile" rather than the name though, as the name may not be consistent across different languages, but the type should be.

To reduce the number of requests / parsing, you can use this fql: "select cover_object_id from album where type='profile' and owner = user_id"

And then you can construct the image url with: "https://graph.facebook.com/" + cover_object_id + "/picture&type=normal&access_token=" + access_token

Looks like there is no "large" type for this image, but the "normal" one is still quite large.

As noted above, this photo may be less accessible than the public profile picture. You need the user_photos or friend_photos permission to access it.

I think I use the simplest method to get the full profile picture. You can get full profile picture or you can set the profile picture dimension yourself:

$facebook->api(me?fields=picture.width(800).height(800))

You can set width and height as per your need. Though Facebook doesn't return the exact size asked for, It returns the closest dimension picture available with them.

Set either the width or height to some arbitrarily large number:

https://graph.facebook.com/username_or_id/picture?width=9999

If the width and height are the same number, the photo is cropped to a square.