def remove_alpha_channel(image):
    """
    Converts the Image object (RGBA or ARGB) to RGB. Just passes it through if already RGB.

    :param image: the image object to convert if necessary
    :type image: Image
    :return: the converted object
    :rtype: Image
    """
    if image.mode is 'RGBA' or 'ARGB':
        return image.convert('RGB')
    else:
        return image