Change wallpapers from any folder, even recursively, with WallPapa
WallPapa is a free program that will change your desktop wallpaper automatically each time you start Windows or in specified time intervals.
Features: Change the wallpaper automatically on start up or at time interval; Change the wallpaper manually; Support of various types of pictures: BMP, JPG, PNG, GIF; Five wallpaper styles: CENTER, TILE, STRETCH, SCALE, COVER;
Wallpapers are chosen from folders of your choice; Wallpaper list can be shuffled; Include/Exclude pictures in subfolders; Find pictures in wallpaper list; Separate settings for each user; Small pictures can be tiled instead of following the selected wallpaper style.
* You may also like to check this free Wallpaper Gadget