Have a look at this website:- http://www.sap.com/australia/index.epx

This is a site from SAP. What I love is how they have rather stunning photos as backgrounds, with a bit of text on top. Striking, and beautiful.

www.about.me do something similar.

The clever bit is - the photos rescale and fill the page no matter what size scree/resolution you use to view the site.

How can I do this using Xara?

The Nivo photo plug-in is the nearest thing I can find, but it doesn't re-scale the image according to the browser/device being used.