Here is a great little White Light Christmas Tree Keynote Theme. This is such a cool little theme, it will showcase your information on the left-hand side of the slide and a very cool image of a Christmas tree on the right-hand side.
This Keynote theme is pretty easy to use and it should work on just about any version of Keynote. Simply download it from the links below and open it in Keynote on your favorite Apple device. You’ll notice just one slide in the Keynote with this background image, to add another simply duplicate this slide by right-clicking or holding down the command button and clicking the existing slide in the slide viewer on the left of the screen and then selecting the duplicate option.
You can adjust how the background fits onto the page by using the option in the format panel in the upper righthand corner.