def _encoded_image_string_tensor_input_placeholder():
  image_str = tf.placeholder(dtype=tf.string,
                             shape=[],
                             name='encoded_image_string_tensor')
  image_tensor = tf.image.decode_image(image_str, channels=3)
  image_tensor.set_shape((None, None, 3))
  return tf.expand_dims(image_tensor, axis=0)