Getting 401 when displaying sensor image

I have a nest battery doorbell and I installed the intergration and it’s working great. However I would like to display the doorbell events in a log book with a thumbnail. The integration provides thumbnail through a trigger so I created a trigger template to track them.

template:
  - trigger:
      device_id: a5c78e051a6db65989c4ad3da041bd8f
      domain: nest
      type: doorbell_chime
      trigger: device
    sensor:
      - name: "Doorbell"
        state: '{{ as_timestamp(now()) }}'
        picture: '{{ trigger.event.data.attachment.image }}'

This almost works, it does display the events with the thumbnail in the logbook however when fetching the thumbnail it gets a 401. In this screenshot you can see a blank space where the image would go.

The DOM for this shows that it does display the right url but it gets a 401.

<state-badge style="background-image: url('https://XXX.ui.nabu.casa/api/nest/event_media/a5c78e051a6db65989c4ad3da041bd8f/WyIxNzEzMzg5MzI1IiwgIm46MSJd/thumbnail');"></state-badge>

Screenshot from 2024-12-14 13-18-05

In my research I found this section on signed paths and that seems like the right solution but I don’t know how to get HA to sign this one.

I’m aware that files put in config/www will be served without authentication and I could probably setup a trigger to copy the files there but I don’t want these images to be publicly accessible.