Set Background in Excel 2010
Unfortunately, you cannot have a background image on your printouts. You may have noticed the Page Layout » Page Setup » Background command. This button displays a dialogue box that lets you select an image to display as a background. Placing this control among the other print-related commands is very misleading. Background images placed on a worksheet are never printed.
Alternative to Placing Background
You can insert a Shape, WordArt, or a picture on your worksheet and then adjust its transparency. Then copy the image to all printed pages.
You can insert an object in a page header or footer.