def convert_docker_params(stack_env=None):
    """Convert Docker* params to "Container" varients for compatibility.

    """
    if stack_env:
        pd = stack_env.get('parameter_defaults', {})
        for k, v in pd.copy().items():
            if k.startswith('Docker') and k.endswith('Image'):
                name = 'Container%s' % k[6:]
                pd.setdefault(name, v)
