I'm not in US - screenshot please?
If you click on the bing icon, though, you also go back to the landing page.
So this little bit of refinement seems to highlight the ever-changing-landing-image as a part of the bing experience.
Then Google copied the background image idea.
Now Bing has gone minimal, but there's obviously still some residual pull/desire around using imagery.
That little strip is a remnant. Like a human appendix it's a residual organ that wasn't completely eradicated as it evolved into the current design.
http://techcrunch.com/2010/06/09/google-adds-a-background-im...