Facebook permissions for viewing photos

I'm writing a Facebook application that accesses the user's friends' photos. For some reason, I can only access certain photos.

I have narrowed it down to only being able to access photos with the 'Friends of Friends' privacy setting turned ON.

The pictures I can't access still have the 'Friends' privacy settings turned ON, but the user the Application is acting on behalf of is friends with these people, so as per Facebook's privacy scheme, I should be able to access them.

I can access the photos via the Facebook site.

My application has the following permissions: user_photos, friends_photos.

I'm not receiving any OAuth errors, I'm merely getting nothing back from the server (e.g. if开发者_JS百科 the user has all their photos set to 'Friends only' I get a blank data{} array from a /UserID/albums API call.

Anyone know what's happening? Should I be requesting more permissions from my App users?

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There's a privacy setting which can override this, check the settings on the friends' account to see what their options for 'How people bring your info to apps they use' setting is - it's on https://www.facebook.com/settings/?tab=privacy and allows users to stop apps their friends use from accessing any data about them, even if it would normally be available to that friend.