session-android/res/layout/album_thumbnail_4.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/album_thumbnail_root"
    android:layout_width="@dimen/album_total_width"
    android:layout_height="@dimen/album_4_total_height">

    <org.thoughtcrime.securesms.components.ThumbnailView
        android:id="@+id/album_cell_1"
        android:layout_width="@dimen/album_4_cell_size"
        android:layout_height="@dimen/album_4_cell_size"
        app:thumbnail_radius="0dp"/>

    <org.thoughtcrime.securesms.components.ThumbnailView
        android:id="@+id/album_cell_2"
        android:layout_width="@dimen/album_4_cell_size"
        android:layout_height="@dimen/album_4_cell_size"
        android:layout_gravity="right|end|top"
        app:thumbnail_radius="0dp"/>

    <org.thoughtcrime.securesms.components.ThumbnailView
        android:id="@+id/album_cell_3"
        android:layout_width="@dimen/album_4_cell_size"
        android:layout_height="@dimen/album_4_cell_size"
        android:layout_gravity="left|start|bottom"
        app:thumbnail_radius="0dp"/>

    <org.thoughtcrime.securesms.components.ThumbnailView
        android:id="@+id/album_cell_4"
        android:layout_width="@dimen/album_4_cell_size"
        android:layout_height="@dimen/album_4_cell_size"
        android:layout_gravity="right|end|bottom"
        app:thumbnail_radius="0dp"/>

</FrameLayout>