Windows 7 Themes not scrolling

[Clingpeach]

Im running 7 Ultimate. When I initally saved a theme South Africa on to my desktop every few seconds the picture kept changing. Now it has stopped it stays on ONE picture. Unless I right click on it and click on next desktop background. How do I enable it to scroll by itself.
Thanks for any help

 

[Clingpeach]

Ah found the answer ...in desktop personalisation.