Allow centered graphic to overflow in margin [duplicate]

Possible Duplicate:
Balancing figure that is wider than document's width

I'm including a graphic with:

\centering\includegraphics[width=xin]{some_name}


This works fine as long as the image doesn't overflow in the margin. When it does, the left of the image is stuck at the margin, and it only overflows to the right.

How can I make it so that the image will overflow in the margin and stay centered?

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marked as duplicate by Jake, Martin Scharrer♦Aug 1 '11 at 14:00

\makebox[\textwidth]{\includegraphics[width=xin]{some_name}}