code: def image_generator(images, labels):
    
    if not images:
      raise ValueError("Must provide some images for the generator.")
    width, height, _ = images[0].shape
    for (enc_image, label) in zip(encode_images_as_png(images), labels):
      yield {
          "image/encoded": [enc_image],
          "image/format": ["png"],
          "image/class/label": [int(label)],
          "image/height": [height],
          "image/width": [width]
      }
docs: Generator for images that takes image and labels lists and creates pngs.
  
    Args:
      images: list of images given as [width x height x channels] numpy arrays.
      labels: list of ints, same length as images.
  
    Yields:
      A dictionary representing the images with the following fields:
      * image/encoded: the string encoding the image as PNG,
      * image/format: the string "png" representing image format,
      * image/class/label: an integer representing the label,
      * image/height: an integer representing the height,
      * image/width: an integer representing the width.
      Every field is actually a singleton list of the corresponding type.
  
    Raises:
      ValueError: if images is an empty list.