You can customize the public calendar by displaying images of your rooms
In your rooms
From the menu, click on Rooms
Select your room and click on the small pencil at the top right:
Upload your new photo and save the changes
In your display
In admin, click on customization to go to the Calendar/Shop tab:
Further down your page, you have different options to display the icons of your rooms. You can choose not to display, display only a small icon or as an image in the background of your room title.
Don't forget to save your changes