Where do I find the wallpapers included in the Deluxe Edition?

To find the wallpapers that are included with the purchase of the Deluxe Edition of the game please do the following:

1. Open Steam and navigate to your Library
2. Find 'Islands of Insight' and right click it
3. Go to 'Manage' and select 'Browse local files'
4. Once there you should see a folder named 'Wallpapers'
5. There you will find two folders containing the vertical and horizontal wallpapers