title: Remove white border around an ImageView
body: <p>My designer keeps adding a little padding around my image.
  I want the image the stick on the top and to fill out the width of the screen.</p>
  
  <p>Here's a screenshot from the designer:</p>
  
  <p><img src="https://i.imgur.com/zsck8.jpg" alt="Screenshot"></p>
  
  <p>This is my XML code:</p>
  
  <pre><code>&lt;ImageView
      android:id="@+id/markertap_header"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentLeft="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentTop="true"
      android:src="@drawable/header_bootsverleih_xhdpi" /&gt;
  </code></pre>