getList returns one page of 100 results.
There is an additional parameter you can use called
page that will let you return page two, page three, and so on.
For this challenge, research the Jetpack Paging Library (developer.android.com/topic/libraries/architecture/paging) and use it to implement paging for PhotoGallery. This library provides a framework for loading your app’s data when it is needed. While you could implement this functionality manually, the paging library will be less work and less prone to error.