Update image on event

Hi there,

I need to display an image in dashboard.
Got that part working by using a template node and simple html.

The problem is, that the file gets updated once in a while (overwritten with a newer version), as it's the output of a opencv script which is executed using the exec node in node-red.
I want the dashboard to reload only that particular cap.jpg once it has been altered. I do not want to constantly pull the image even though it hasn't been changed.

Do you guys have a hint for me? It has to be a offline solution though, no Internet!
The exec node returns a '0' on successful execution so we could use this as trigger.
I am very new to javascript and html, so I am not sure how to implement an event that only partially refreshes the dashboard on a defined event.

A hope it's clear what I want to achieve. I have been searching the web for hours but have yet to find a solution to my issue.

thanks :slight_smile: