nativescript-demo/App_Resources/Android/src/main/res/drawable-nodpi/splash_screen.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:gravity="fill">
    <item>
        <bitmap android:gravity="fill" android:src="@drawable/background" />
    </item>
    <item>
        <bitmap android:gravity="center" android:src="@drawable/logo" />
    </item>
</layer-list>