Can't get Nest Hello doorbell to send snapshot to iphone

I’ve read through bunch of examples online and I can’t figure out how to do this. I have a Nest Hello doorbell and want to send a notification to my iPhone when someone presses the doorbell with a snapshot or gif of who is at the door. I can send the basic notification to my phone, but can’t get any snapshot or gif to work. Is there any definitive guide/example on how to do this? There’s an example of this in the documentation (below) but it doesn’t work. I’m guessing I’m missing something.

action: notify.mobile_app
data:
message: Doorbell Pressed
title: Someone pressed the doorbell
data:
image: “{{ trigger.event.data.attachment.image }}”

I kind of got this working but not in the way I’ve seen online. I basically take a snapshot using camera snapshot and then put a local URL to where the snapshot is stored. Not sure why the examples don’t work. Is it because it required something like nabu casa?