<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginBottom="4dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="4dp"
        card_view:cardElevation="2dp">

        <ImageView
            android:id="@+id/catImage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="16dp"
            android:adjustViewBounds="true"
            android:scaleType="centerCrop"
            tools:background="@android:color/holo_blue_dark"
            tools:ignore="ContentDescription" />
    </android.support.v7.widget.CardView>
</FrameLayout>
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginBottom="4dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="4dp"
        card_view:cardElevation="2dp">

        <ImageView
            android:id="@+id/catImage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="16dp"
            android:adjustViewBounds="true"
            android:scaleType="fitCenter"
            tools:background="@android:color/holo_blue_dark"
            tools:ignore="ContentDescription" />
    </android.support.v7.widget.CardView>
</FrameLayout>
Change scale type to ensure images are square
Change scale type to ensure images are square
