Once you've decided the kind of background you'd like to use, it is a good idea to double check your background settings to make sure they match up with the background you're using. In our background library, there are both "tiled" and "full page" backgrounds. Check on which type of background you've chosen before you change your background settings.
To access your background, first click on the icon for your Builder.
From there, hover over design and click on site background.
The initial page you land on (images) will show you the type of background you're currently using. Note if it is a tile background or a full page background.
Click on the settings tab and select the setting that goes with the type of background you're using best. The most common settings are Tile (for tile backgrounds) and Scale to Fill (for full page backgrounds).