Not that I'm aware of currently.
One possible way to work around this is to allow the user to specify a URL to download an image to use if they are selecting your enhanced idle app, and then the app can fetch that to a file and then display it on the screen. You can take a
screen shot if you want to get the default images and then provide those via the same utility that you allow the user to configure a new image.
Not ideal...but still possible....