It is possible to change the pre-configured slideshow of images to a single image by following the steps below:

• Open the Settings menu by pressing the hamburger menu button (bottom left). 
• Go to "Personalization".
• Then you can enter a web URL of a JPG or PNG file.

Please note that at this time, it is not possible to use animated or locally stored images. It's also not possible to set your own video or slideshow.