When you add a background image to a page there are 3 different settings that you can use:
This option ensures that the background image takes up the full of the page.
When you use this option some of your image may be cropped out of view. When this happens you can move the image around within the page by using the horizontal and vertical sliders:
This option will ensure that your image is repeated several times to fill the entire page area.
You can place your image anywhere on the page background with this option:
Use the horizontal and vertical sliders to move the position of the image on the page: