@dlongm01
The CTRL+F5 approach actually only does a hard refresh. However, most browsers also have the ability to do a more extensive clearing of the cache. The issue though is that this would only address the browser cache.
There are a number of different types of caching that can take place at different locations. There is the browser cache, WordPress caching plugins, object caching, reverse proxy caching, etc.
Most likely, you have one of the two happening:
1. A WordPress caching plugin is serving up the same content for all logged out users until the page is updated again in WordPress (which would generally clear the cache for that page).
2. Your web host is running a reverse proxy cache that serves the same content unless it has reason to believe it shouldn’t. It is common that a reverse proxy cache won’t cache when cookies are set, such as those used when you are logged into WordPress.
So, if you know you have a certain caching plugin active or want to divulge which web host you are using, I can provide a bit more detail on what specifically might be going on. In the case of #1, you may be able to add a rule to not cache the page(s) on which you want the images to display at random. In the case of #2, you may be able to contact your host and set up similar rules, or you may be able to leverage your host’s built-in cache busting to overcome the issue.
