By not using internet. No, seriously, if you access something over the internet, you will leave tracks. This here post is nothing new or inherently scary on its own. I used to have forum signatures that would tell people what browser they were using or from what IP they were coming.
What you really want to do is disable third party cookies on everything you own. That (and things like hsts super cookies) is what tracks you.
If you’re using an app to browse Lemmy, you might ask for their implementation to reject cookies and fingerprinting attempts when displaying images and other embeddables.
a minute later edit: And yeah, if you don’t like web services to know the IP address given to you by your ISP, VPN is a decent option.
I would say a user agent spoofer would be more useful for this particular image. The Mozilla team recommends User-Agent Switcher and Manager for Firefox users.
That's weird. The extension should definitely work with the image, as that's what I used when building this quick demo. Does the content of a site like this update?
TL;DW: Click on the extension icon, use the drop-down lists to find a browser and OS, select a pre-configured user-agent string from the list, and click "apply (container)" or "apply (all windows)". Having your user-agent string change randomly with each request is possible but requires writing a bit of JSON in the options.