title: Flow saying "Required module not found" for <Image> sources
body: <p>We have an existing React Native project (version 0.22.2) and I'm trying to set up the Flow type checker (version 0.23) on certain files. However, Flow is giving a lot of errors for the <code>require()</code>s calls we're using for <code>&lt;Image&gt;</code> sources. For example, we have this code in one of our components in Header.js:</p>
  
  <pre><code>&lt;Image source={require('./images/nav.png')} style={styles.navIcon} /&gt;
  </code></pre>
  
  <p>Which React Native handles fine and it works. However, Flow seems to be trying to treat the <code>require()</code> as a regular module require and not finding it, and giving errors like this:</p>
  
  <pre><code>Header.js:30
  30: &lt;Image source={require('./images/nav.png')} style={styles.navIcon} /&gt;
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ./images/nav.png. Required module not found
  </code></pre>
  
  <p>How can I tell Flow to stop giving these errors? I've tried adding <code>.*/images/.*</code> to the <code>[ignore]</code> section of my <code>.flowconfig</code>, but that doesn't change anything.</p>