Random Wallpaper will change the wallpaper on your phone at the selected interval you choose. (This does not work with live wallpapers.) You can select up to 6 images you want to cycle through, randomly or sequentially, to place into the gallery. Note, this application only stores a reference to the image, so if you remove the image off of the phone, it will not be in the gallery.
You can optionally have it only change only during certain hours. It can also optionally turn off the wallpaper changing service when the phones battery reaches a certain power level.
It can also be set to only change the wallpaper when the phone is plugged into power.
This application is supported by ads and is limited in the amount of images it can store in the gallery and also the length of time it will stay running. You will just need to restart the wallpaper changing service to continue changing the wallpapers.
The paid version of this app does not have any limits to the amount of images that can be stored in the gallery and does not have a limit on how long the service will continue running. There is also a widget included with the paid version that allows you to change the wallpaper with the touch of one button. The paid version can be located here.