That is very weird, the map is uploaded as a low res jpg only. It would be impossible to get the individual layers.
I just tried scrolling in and out in WPV and it works fine for me lol.
If the problem remains, the only thing I can suggest is right click the image > properties > 'Change..' button > select 'Windows Live Photo Gallery'.
If you don't want to do that, delete the image and download it again.