Load anns with the specified ids.
        :param ids (int array)       : integer ids specifying img
        :return: imgs (object array) : loaded img objects

def loadImgs(self, ids=[]):
        """
        Load anns with the specified ids.
        :param ids (int array)       : integer ids specifying img
        :return: imgs (object array) : loaded img objects
        """
        if _isArrayLike(ids):
            return [self.imgs[id] for id in ids]
        elif type(ids) == int:
            return [self.imgs[ids]]