By the way, other updated browsers (Chrome and Vivaldi) display this NOAA site's animation loops without any issues.

Site works for me. see screenshot You need to look at the web developer tool(CTRL+SHIFT+I) and see there's anything under the debugger and network.

What security software are you running?

Are you running pro version of Windows? If so, you should have Windows Sandbox enabled for testing. https://www.howtogeek.com/399290/how-to-use-windows-10s-new-sandbox-to-safely-test-apps/

You can also boot windows to safe mode with networking and see if you have the same issue.

System info: Laptop, desktop, or DIY? If not DIY, what make and model?

I have Bitdefender and have been running it for many years. The GOES West satellite animations have always worked on Firefox for me for many years. It wasn't until the last insistent update, or two, that it stopped. I see the picture but not the animation. I'm running Windows 10 Pro and have been on my Thinkpad X1 Carbon gen 10 since I bought it in Sep 2022. I didn't see anything in the debugger. In the network I saw what looks like 24 images with a slightly different name so it looks like the animation isn't working on my version of Firefox.

Hmm, network, eh? I am using Express VPN and that does break some sites, although there's been no problem with it until the last update (or previous). So, I shut down the VPN and voila` - it's now working.

Ugh. Thanks for thinking of this. I have to remember that the more I secure my machine(s) and network the more things on the internet don't work. Sigh...

Thanks again!