You can cycle your background picture with OS X. No need to install anything.
However, you have to have the pictures first

There are many dedicated desktop background sites which should satisfy anyone's need (girls, cars, art, etc.).
1 Put all pictures you want to use in one folder.
2 You go to the System Prefs, click in Desktop & Screen Saver.
3 Select Choose Folder and choose the folder which contains all your pictures.
4 Tick the checkbox on the bottom and set an interval (30 minutes or whatever).
5 Done.