1. Select Format > Styles.
2. In the Styles: window, select Background + Text (BODY),
and click Modify...
3. In the Modify Style window, click Format and select
Borders and Shading.
4. In the Borders and Shading.window, select the Shading tab.
5. In the Pattern > Image area, browse for your image and
experiment with the other settings until you get what you want.
Good luck,
Leon