Force reload without cache?

[Jonisos]

The problem: I am trying to display a webpage which only contains one image which only refreshes after I refresh the webpage in a regular browser. I can see in the image when it was requested for the last time. So when I set the timer in SmartWebDisplay I would expect the image to refresh after the given time but it does not work. The refresh time seems to be ~4h but this is not consistent.

I already tried to include 2 URLs to maybe force a fresh reload but this does not help.

I am wondering if the image is being cached and therefore not fully requested every time? Any ideas on how to solve this issue?