main_activity.xml

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".MainActivity">

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin">

        <com.android.volley.toolbox.NetworkImageView
            android:id="@+id/userImageView"
            android:layout_width="96dp"
            android:layout_height="96dp"
            android:layout_marginTop="16dp"
            android:adjustViewBounds="true"
            android:src="@mipmap/ic_launcher_round"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toLeftOf="@+id/horizontal_middle"
            app:layout_constraintTop_toBottomOf="@+id/userNameTextView" />

    </android.support.constraint.ConstraintLayout>
</layout>