Add a banner image
Open the Page Inspector, select the 'Styles' tab at the top and then click the 'Banner/Header Image'. Choose one of the file names listed for your banner.
Now, navigate on your computer to /Users/username/Library/Application Support/RapidWeaver. Right-click on NSPOne.rwtheme and choose 'Show Package Contents'. This will show open the folder of files that make up the theme. In that folder is another folder called 'images'. Copy and paste the image you want to use for the banner into this 'images' folder and rename it according to the file name you chose in the page inspector (i.e. banner01.jpg, banner02.jpg, banner01.png, etc.).
Click Preview and voila!
Note: Banner images should be 140px and be the width chosen in the 'Page Width' option in the page inspector when the 'Logo' option is turned off. When 'Logo' is turned on simply subtract 270px (width of logo) from the chosen page width. Example - Page Width chosen is 800px therefore 800-270=530. This means your banner should be 530px wide to fit next to the logo when the page width is 800px).