desktopmacoswallpaper
In OnyX, there is a setting in Parameters > General > Animated desktop background: where animated wallpapers can be set. While this doesn't seem to work very seamlessly (moving between spaces displays old wallpaper briefly etc.) and doesn't persist over restarts, I wonder how OnyX does this.
Is there some hidden setting where one can do this without OnyX?
Note that my question is not about how to set gifs as wallpapers (although maybe this is what OnyX does?).
System: 10.11.5
Open ~/Library/Safari/.
It is there, called Safari Desktop Picture.jpg (or whatever the extension is).
If you're on Lion, to get to Library folder you may open Finder, select Go from the top menu and hold ⌥ Option. The normally hidden Library menu will reveal itself in the folder list. Open it, and proceed to Safari subfolder.
If you're not on Lion or just prefer the quick way, open Finder, press ⇧ Shift + ⌘ Cmd + G to open directory prompt and paste ~/Library/Safari/:
You can use Mojave's dynamic wallpaper. macOS doesn't natively support animated GIFs as wallpapers.
However you can use this https://lifehacker.com/set-an-animated-gif-as-your-macs-wallpaper-1756859302 but at the cost of a shorter battery life for a wallpaper that you probably wouldn't see in action because you got windows all over.
Your case is more like needing a really thin phone(GIF) which you are gonna cover with a case(windows) anyways.
Best Answer
Yes, this can be done without OnyX.
Source: How to Set a Screen Saver as the Desktop Background in Mac OS X