If you want to change the main background image on your LiveEditor page, you can follow these steps:
- In the LiveEditor n the left side menu select "Colour Scheme Settings"
- Click "Page Colour Settings"
- Then "Overall Page Colour Options"
- You will see the background image and you can choose or upload an image here
Note that this option is separate to the Row background settings. If you want to change the row background image, see this tutorial