To create a background image for Luke Barnett, we can use CSS. Here's an example of how to do it:

body {
  background-image: url('https://example.com/luke-barnett-background.jpg');
  background-size: cover;
  background-position: center;
}

This code sets the background image to https://example.com/luke-barnett-background.jpg, scales it to cover the entire page, and centers it. You can replace the URL with your own image.

Note: Make sure to replace 'https://example.com/luke-barnett-background.jpg' with the actual URL of the Luke Barnett background image you want to use.