Issues attaching photos to iOS push notifications

Configuration
,
1

I've created a notification to alert me to status changes from my BambuLabs 3D printer, and I'm trying to get it to include an image of the current item being printed (which is something already exposed by the integration as an entity), but I'm having difficulty getting the notification to actually include the image attachment.

The image is provided in the entity image.office_bambulab_p2s_cover_image, so ideally I could just include it from the entity directly, but I haven't been able to figure out how to do that. So instead, my automation takes an image snapshot from that image entity, saves it to a local file, and then I attempt to send the notification including that file as an attachment. When I do that, I get the notification, but it includes an image indicating that it failed to load the attachment:

IMG6213
IMG62131206×624 82 KB

Here's the YAML for the action as it stands currently:

action: notify.mobile_app_iphone_17_pro
metadata: {}
data:
  title: BambuLab P2S Status Update
  data:
    url: /dashboard-mobile/printing
    attachment:
      media_source: /media/local/current_print.png
  message: >-
    Warm-up complete, print has started. Estimated completion at
    {{as_timestamp(states("sensor.office_bambulab_p2s_end_time")) |
    timestamp_custom("%I:%M %p")}}

I've placed the image file in my /media directory, and I can view it in Media > My media, so I know that the file is valid and in a place where HA can see it. I placed in in /media rather than /config/www because it seemed like a good idea not to expose it to the internet if at all possible, but now I'm wondering if images have to be in www in order to be visible in push notifications. I get the same issue if I change the media_source path to /local/current_print.png

I've confirmed that when I view the image in My media, the URL is

http://homeassistant.local:8123/media/local/current_print.png?authSig=blahblahblah

I have also tried providing a url instead of media_source but that doesn't work either:

  data: 
    attachment: 
      url: "/media/local/current_print.png"

So my questions are:

  1. Is there a way to just include the image directly from the image entity?
  2. If not, what am I getting wrong about including the image from a local file?