GKLocalPlayer getting profile pictures

I'm working with Game Center Kit, how can I get the image of game center use开发者_如何学Pythonr(my friend, or anyone else) thnx

There is an asynchronous method to load either a small or normal sized player image (only available in iOS5):

- (void)loadPhotoForSize:(GKPhotoSize)size 
   withCompletionHandler:(void (^)(UIImage *photo, NSError *error))completionHandler