Comment force Windows desktop background to mise à jour or refresh

[Clippy]

Si je manuellement changez le background image dans le registry, how puis-je force it to refresh sans logging off?

Je sais that [bginfo](http://technet.microsoft.com/en-us/sysinternals/bb897557) does it, but Je voudrais keep things simple and not use any logiciel.

[Clippy]

```
RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters 1, True

```