Supposing that you have pictures in folder, you can create a method that iterates over the folder and creates a List of ViewModels. A ViewModel class can hold a Name(string) of the picture and Path (of type Uri) to it. Then you have to create template for the Left and Right Pages and bind the ItemSource of the Book to the list you created. Nothing special here, the mentioned demo and this help article should be a good starting point.
This msdn article may also be helpful.
As for the demo and the namespace viewmodels"
you can see it is only used to define the PageCollection:
Which is actually in the MainPage.cs file:
public class PageCollection : ObservableCollection<
You can create this PageCollection class (or class with similar name) and use the local namespace pointing, for example like so:
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