Adding an image to the woocommerce admin order page which the customer can view

Hi all, so I have tried searching in several places and using several different terms, i cant seem to find what i want….

Basically I send out some of my orders to customers with no proof of postage as they are simply stamped, addressed envelopes, I would like to be able to add a picture to the woocommerce admin order notes to send to the customer so they can see the envelope with their address on it and a stamp attached, either way i want to be able to add it to the order page so that the customer can view the picture once i have dispatched it.

Does anyone know a method or plugin that will allow me to do this?