There are many free apps to change the desktop wallpapers automatically including the default option available in Windows 7. Kuvva is yet another freeware app available for both Windows and Mac lets you automatically change wallpapers from its collection. Another useful feature of Kuvva is that you can also rotate your Twitter web backgrounds using the app. You need to authorize the app to access your account and the app does the rest. You can create a free account with Kuvva, the advantage of having a free account (not mandatory) is that you can add wallpapers to your collection and use them at a later stage.
The app runs from the system tray and automatically changes the wallpapers. You can also change them from the system tray icon. If there are any wallpapers you particularly like, you can choose to ‘love’ them and they can then be accessed easily through your online account should you wish to use them in the future.
Kuvva is available for both Mac and PC and is a great way to give your desktop a fresh look with new wallpapers.