You can add your own custom kiosk background to make them look even better in the Windows app. To do this, you need to have the images in the dimensions & size of your Windows tablet
You can use software like Photoshop or Indesign to create them, but if you do not have that kind of software, you can always use this free online tool:
Go to the kiosk you wish to give a (new) background and select this kiosk.
You'll see that more options will be added to your screen. Choose the "camera".
Now add the picture you wish to use as a background according to the settings that you see on the screen.