SwapWall is a very easy to use application that can cycle the pictures that you want to put on the background of your desktop.

The program enables you to add individual files or entire folders at once. SwapWall can change the wallpapers at a time interval you specify in the main window. Manually assigning an image to be displayed on the desktop is also possible. The pictures can be used either in order or randomly, depending on your preferences.

Key features include:
Can change wallpaper automatically after a specified time period (e.g. every 5 minutes)
Displays images randomly or sequentially
Supports JPG, PNG, BMP file formats.
User friendly interface. Original design
Can change wallpaper on every Windows startup
High quality image resize
Use a system tray icon for an easy control of the software
Display a preview of selected wallpapers
Customizable Global Hotkeys - Quickly change/clear the wallpaper with any key combo.
Very high quality resizing of images.
Uses very little resources.
Portable