Well, bad news first: No photos as a background in the Metro style touchscreen. Photos apparently would be hidden by the tiles, and wouldn’t stretch/scale as you add more tiles. Good news? You have (presently) 8 different styles from curlicues to rectangles and squares. and a shade picker from a scrollbar color picker. Not all tiles will conform to the shading of certain color picks, though.

You can use your scrollwheel to swipe sideways, and there’s a “semantic zoom” (pinching the screen to see tiles as groups of tiny icons and then choosing a group to zoom in on (as a quick search instead of swiping through screens of full sized tiles).

By clicking on the Windows icon, you can go from the Tiles to a taskbar/start menu traditional desktop, and I believe this will be customizable for Windowblinds and wallpaper, as well as your other SD apps. The upper arrow shows the non shading tile.

I’m rather disappointed by the “No Photo, Our Wall” in metro, also by the currently very limited choice of backgrounds (although that could expand).

Sources and photo credits:

http://www.ghacks.net/2012/01/28/windows-8-metro-ui-wont-allow-custom-backgrounds/?_m=3n%2e0038%2e413%2ehj0ao01hy5%2ef2p

http://www.techradar.com/news/software/operating-systems/windows-8-beta-more-personalisation-coming-1057390 (and photo credit)