I think there is no way to set the lock screen wallpaper on the iPhone programmatically (with ref to this question), but with the 3.2 SDK and the ability to set the wallpaper on the home screen on the iPad, does the SDK allow this to be done via APIs now?
I looked up the developer reference, but i could not find anything useful.
I don't think there's a method for that. The user can change it in the settings. But if you could change it progmatically, I'm sure there would be a lot of people who would abuse it...
来源：https://stackoverflow.com/questions/2612160/setting-the-wallpaper-on-an-ipad