Embed Image in Notification

I’ve been trying to find a way (through searching online) to embed an image into the notification - at the time of the notification - from an external source. I have a bit to python running on a server which, when called as a URL returns an image from a camera. If I add this URL to the notification it successfully launches the browser and displays the image but this is usually a few seconds after the event so usually misses the action. How do I do this through the actual notification in PushCut? Is there a guide I could follow?