Here is a free wallpaper rotator
(This is an excellent program!)
With this, you can have your computer rotate through all these. :) I'll edit this post as necessary with more helpful info. I'm going to get all these files & put this on my wife's computer.
All you have to do is install this freeware program, then add all the pics you download. You can rotate every 30 minutes, or however often you like, or every time you reboot.