Hangouts image attachment supposedly fixed, but is is?

I hope, you don’t mind, if I pick this

Allow Image Attachments in Hangouts Notification:

up here again, but according to github (here and here) this is supposed to be fixed, so it is not a “Feature-Request” anymore

Unfortunately I still can not attach an image to a hangouts-message through notify-Service, while calling the hangouts.send_message service in the dev-tools works perfectly.

Here is my JSON for the dev-Tools:

{
  "message": [
    {"text": "message"}
  ],
  "target": [
    {"id": "<conversationid>"}
  ],
 "data": 
   {"image_file": "/config/www/cam_captures/snapshot1.jpg"}
}

And here is an automation that tries to send an image attachment:

- alias: test
  trigger:
    platform: template
    value_template: "{{false}}"
  action:
    - service: camera.snapshot
      data:
        entity_id: camera.ip_webcam
        filename: "/config/www/cam_captures/foto.jpg"
    - service: notify.hangouts_seanomat
      data:
        message: "Text 01"
        image_file: '/config/www/cam_captures/foto.jpg'
    - service: notify.hangouts_seanomat
      data_template:
        message: "Text 02"
        image_file: '/config/www/cam_captures/foto.jpg'
    - service: notify.hangouts_seanomat
      data_template:
        message: "Text 03"
        data:
          image_file: '/config/www/cam_captures/foto.jpg'

I am not quite sure, how to attach the image, so I tried different methods. The first two calls to notify are ignored, if images are attached (they work if you comment out the images).

This error is generated in the log

Invalid service data for notify.hangouts_seanomat: extra keys not allowed @ data[‘image_file’]. Got ‘/config/www/cam_captures/foto.jpg’

So, am I doing something wrong? Is this actually fixed as the github-issue suggests? Might the fix not be in the current version of home-Assistant jet (im using 0.81.2 right now)?

What to do?

ever figured this out?