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 NSPThree.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 in height and be 600px wide when the 'Logo' option is turned on - 902px wide when 'Logo' is turned on.
IMPORTANT: Any square/rectangular logo or banner image will flow over the large rounded page corner. You will need to have the rounded corner on the opposite side of the banner or choose Square from the Page Background style settings.