def _rotate_images(process_me):
    """
    Rotates the images given in process_me by all four possible 90 degrees.
    """
    results = []
    for orig_im in process_me:
        results.append(orig_im)
        rotated_im = orig_im
        for i in range(3):
            rotated_im = rotated_im.rotate(90)
            results.append(rotated_im)
    return results