In the scheduled recordings view, for shows that have not been recorded previously, there is a blank poster with the show name on it displayed.
If you highlight the blank poster, the description of the show from the guide comes through, so the details to pre-fetch the artwork should be available and it would be nice if the app could pull them down so that the scheduled recordings view was cleaner.
I put this in the latest beta... Within 12 minutes of scheduling a new series/recording (or starting the service) it will prefetch the artwork for recordings that haven't been recorded before. It may not be as accurate but I guess it is better than nothing. There is also an option in the Recorded TV HD settings in the Media Center UI to under other interface options to enable prefetching the poster on demand if the artwork hasn't yet been downloaded by the service (which could take a little longer to show the scheduled recordings).