I second "MultiPicture Live Wallpaper" as suggested above. Download it from the market, tap Personalize/Wallpaper/Live wallpaper, select MultiPicture, tap Settings, then you can tell it which folder(s) you want to pull the pictures from (I downloaded a bunch of photos from Google Images, organized them into folders on my computer, then attached my Thunderbolt to my computer as a disk drive to load them on there), and adjust/tweak the settings according to your preferences. I have a different picture for each of my 7 screens plus the lockscreen. Doubletap a screen to get a whole new set of pictures from the album(s). You can adjust the interval they change, and the transition animation. I suggest having a lot of pictures to choose from in your folder(s), because the randomizer used in this app is not the best so sometimes you will get the same picture on multiple screens if there is not a lot to select from. Other than that one small gripe, its a really great app!