Weird behavior persistent notification with image

I create a camera.snapshot image and save it to the same file again and again. When I email the image or send a notification to my mobile, it shows the last image saved.

However, when I send the same image using a persistent notification, it shows the first image saved. If I change the filename of the snapshot, it shows that image, but as soon as I overwrite that image, it continue to use the first image when I send a new persistent notification.

Any ideas?

  variables:
    local_file: '{{ snapshot_file | replace("/config/www","/local") }}'
  sequence:
  - service: persistent_notification.create
    data:
      message: '{{ snapshot_message }}<br /><br />![image]({{- local_file -}})'
      title: '{{ snapshot_title }}'

I cleared the browser cache, logged back into Home Assistant and now it shows the last image in all notifications.

It seems that persistent notification have a link to the image and use that or if the image is cached by the browser, use the cached image.

Is my understanding correct? And if so, is there way for persistent notifications to show the image I would like it show other than creating unique filenames each time I create a snapshot?