Signal-Android/app/src/main/res/layout/mediarail_media_item.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    tools:viewBindingIgnore="true"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="@dimen/media_rail_item_size"
    android:layout_height="@dimen/media_rail_item_size"
    android:layout_margin="4dp"
    android:animateLayoutChanges="true">

    <org.thoughtcrime.securesms.components.ThumbnailView
        android:id="@+id/rail_item_image"
        android:layout_width="44dp"
        android:layout_height="44dp"
        android:layout_gravity="center"
        android:background="@drawable/mediarail_media_outline"
        app:thumbnail_radius="8dp"/>

    <ImageView
        android:id="@+id/rail_item_outline"
        android:layout_width="46dp"
        android:layout_height="46dp"
        android:layout_gravity="center"
        android:src="@drawable/mediarail_media_outline"
        android:visibility="gone"
        tools:visibility="visible"/>

    <ImageView
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_gravity="center"
        android:src="@drawable/mediapicker_item_border_dark"/>

    <ImageView
        android:id="@+id/rail_item_caption"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="start|top"
        android:layout_marginStart="2dp"
        android:src="@drawable/ic_caption_28"
        android:visibility="gone"
        tools:visibility="visible"/>

</FrameLayout>