1. go to S2U2 Settings
2. scroll down to Wallpaper:>File Directory (click until you get to option 3 or option 4 it depends on if the pictures are on your device or SD card) do this for both portait and landscape
3. scroll down a lil to Change JPG Wallpaper Every> your desired time.
4. Change JPG Wallpaper Randomly turn it on
and your done.
I attached two screen shots to help you out a lil more I know it always helps me. Also
http://forum.xda-developers.com/showthread.php?t=381588 is where you can download the newest version. Good luck and have fun.