code: private void initTopImage() {
          views.fullImageToolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp);
          views.fullImageToolbar.setNavigationOnClickListener(view -> onBackPressed());
  
          imageAnimator = GestureTransitions.from(views.appBarImage).into(views.fullImage);
  
          // Setting up and animating image transition
          imageAnimator.addPositionUpdateListener(this::applyFullImageState);
  
          views.appBarImage.setOnClickListener(view -> {
              getSettingsController().apply(views.fullImage);
              imageAnimator.enterSingle(true);
          });
      }
docs: Initializing top image expanding animation.