[O] [org-contacts] How to show avatar image on org headings?

[stardiviner]

I want to show org-contacts avatar image on org-headings.
Use overlay, or there is other better methods?

A sample org-contacts snippet looks like this:

* [] John KK
:PROPERTIES:
:AVATAR: john kk.jpg []
:END:

I want to display the image at [] on heading, or replace "john kk.jpg"
with [] image.

BTW, another question, how to get property's value? and how to iterate
on all heading elements then auto display image when open Contacts.org
file?

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