gistfile1.txt

 on_setup:
  - setup_png_storage:
    request:
      method: put 
      uri: /{domain}/sys/key_value/postservice.png

on_request:
  - try_storage_and_return:
      request:
        method: get
        headers:
          cache-control: '{cache-control}'
        uri: /{domain}/sys/key_value/postservice.png/{hash}
      return_if:
        status: [ 200 ]
  - get_post:
      request:
        uri: /{domain}/sys/post_data/postservice/{hash}
  - new_png:
      request:
        method: post
        uri: http://some.post.service/png
        body: '{$.get_post.body}'
  - save_new_png:
      request:
        method: put
        uri: /{domain}/sys/key_value/postservice.png
        headers: '{$.new_png.headers}'
        body: '{$.new_png.body}'
      response: '${$.new_png}'