[Pythoncard-users] Dynamically changing background image?

I'm trying to change the background image of my PythonCard application after
its been initialized, and having trouble.

By "background image" I mean the image that we set from Background Info -->
Image.

I can dynamically change the background color like this:

self.backgroundColor = (255, 255, 255)

And looking at the resource file, the image is in a key called "image". But
this doesn't work:

self.image = whatever.jpg

Is there some other trick to it?