Windows 8 Consumer Preview released a few days ago introduced a lot of new things, including Panoramic themes for your Desktop. This works very good for 2 displays config wich got the same resolution, if they don’t have the rame resolutions then a different image will appear for each of the monitor.
Nightfall and Starlight panoramic theme can only be used in Windows 8 Consumer Preview or Windows Developer Preview.
- Panoramic images will automatically extend across both displays of a dual-monitor setup if both monitors have the same resolution settings. If the displays are different sizes or have different resolution settings, a different image will appear in each monitor.
- Panoramic themes can be used on single monitor setups, but only the center part of the image will be visible.

Also, if you don’t have a dual monitor setup, you can still run this themes, it will automatically set for a single monitor.