def sg_summary_image(tensor, prefix=None, name=None):
    r"""Register `tensor` to summary report as `image`

    Args:
      tensor: A tensor to log as image
      prefix: A `string`. A prefix to display in the tensor board web UI.
      name: A `string`. A name to display in the tensor board web UI.

    Returns:
        None
    """
    # defaults
    prefix = '' if prefix is None else prefix + '/'
    # summary name
    name = prefix + _pretty_name(tensor) if name is None else prefix + name
    # summary statistics
    if not tf.get_variable_scope().reuse:
        tf.summary.image(name + '-im', tensor)