canon_target =
  (#exact-list [#exact-symbol "target"] canon_text)

canon_size =
  (#exact-list [#exact-symbol "size"] #any-symbol #any-symbol)

canon_image_name =
  (#exact-symbol "image")

canon_image =
  (#choice [
    (#variadic [canon_image_name canon_target] canon_text_or_include)
    (#variadic [canon_image_name canon_target canon_type] canon_text_or_include)
    (#variadic [canon_image_name canon_target canon_size] canon_text_or_include)
    (#variadic [canon_image_name canon_target canon_size canon_type] canon_text_or_include)
  ])
