Possible to have a left and right background margin?

I would like to use a background image which is displayed behind the mainbody area.

So not a background image that appears behind the text but a background image which only will be visible on the right and left margin.

Let me know if you do not understand

Is this possible?

Hi,
If I understand well you need margin for background?
1) You can use background-size property.
2) Or you can add white (or transparent) borders to background image /use photoshop/.