ALAuthorizationStatus status = [ALAssetsLibrary authorizationStatus];

[assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
        if (*stop) {
            return ;
        }
// TODO : access granted
    *stop = TRUE;
    } failureBlock:^(NSError *error) {
        // TODO: User denied access. Tell them we can't do anything.
    }];