Push command over web

I’ve built a project where the sales staff for a nightclub can upload a client logo to my website. Then when they get to the actual night club they push a button and it refreshes the website in touchdesigner and displays that logo on the screens of the nightclub. Without constantly polling the website, is there a way to eliminate the refresh button? Like some sort of web listening side program or something?

Depends on how deep you want to go. Simple solution would be a WebClientDAT regularry polling your website (text only, so not to harsh) and comparing it to a localy stored version of that website. If they differ you force the reload and update your local version of the website.
(This of course only works when something in your website changes like the path to the image.)
If the path to the image is always the same you can of course to the same with the image data (should not be to big right?)

Another solution would be setting up your own server with a simple node-server (for example node-red might be of help). You can then connect to that server via WebSockets abd use a webhook from your CMS where you upload the image to send a message to touch from the node server.