cached_images:
  description: |
    A list of cached image JSON objects, possibly empty, where each
    object contains the following fields:

    ``image_id``
        The id of the cached image
    ``hits``
        The number of cache hits for this image.
    ``last_accessed``
        Epoch time when the cached image was most recently accessed.
    ``last_modified``
        Epoch time when the cached image was installed into the cache.
    ``size``
        Size in bytes of the cached image.
  in: body
  required: true
  type: array
queued_images:
  description: |
    A list of image ids, possibly empty, of images queued to be
    cached, listed in the order in which they will be processed.
  in: body
  required: true
  type: array