session-android/res/layout/thumbnail_view.xml

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:app="http://schemas.android.com/apk/res-auto">

    <ImageView android:id="@+id/thumbnail_image"
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:adjustViewBounds="true"
               android:scaleType="fitCenter"
               android:contentDescription="@string/conversation_item__mms_image_description"
               android:layout_margin="@dimen/media_bubble_border_width" />

    <com.pnikosis.materialishprogress.ProgressWheel
            android:id="@+id/progress_wheel"
            android:layout_width="70dp"
            android:layout_height="70dp"
            android:layout_gravity="center"
            android:background="@drawable/progress_background"
            android:visibility="gone"
            app:matProg_barColor="@color/white"
            app:matProg_linearProgress="true"
            app:matProg_spinSpeed="0.333" />

</merge>