title: Icons/Images do not display with TabBarBottom in React Native
body: <p>I've pretty much taken the sample code from the TabNavigator documentation and the icon's/images simply don't appear on iOS or Android. Even the label override doesn't seem to take effect. What am I doing wrong?</p>
  
  <p><a href="https://i.stack.imgur.com/3z0VQ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/3z0VQ.png" alt="enter image description here"></a></p>
  
  <p>Here's the link to the docs I've been using: 
  <a href="https://reactnavigation.org/docs/navigators/tab" rel="noreferrer">https://reactnavigation.org/docs/navigators/tab</a></p>
  
  <p>Here's my code:</p>
  
  <pre><code>class MyHomeScreen extends React.Component {
    static navigationOptions = {
      tabBarLabel: 'Not displayed',
      // Note: By default the icon is only shown on iOS. Search the showIcon option below.
      tabBarIcon: ({ tintColor }) =&gt; (
        &lt;Image
          source={require('./chats-icon.png')}
          style={[styles.icon, {tintColor: tintColor}]}
        /&gt;
      ),
    };
  
    render() {
      return (
        &lt;Button
          onPress={() =&gt; this.props.navigation.navigate('Notifications')}
          title="Go to notifications"
        /&gt;
      );
    }
  }
  
  class MyNotificationsScreen extends React.Component {
    static navigationOptions = {
      tabBarLabel: 'Notifications',
      tabBarIcon: ({ tintColor }) =&gt; (
        &lt;Image
          source={require('./notif-icon.png')}
          style={[styles.icon, {tintColor: tintColor}]}
        /&gt;
      ),
    };
  
    render() {
      return (
        &lt;Button
          onPress={() =&gt; this.props.navigation.goBack()}
          title="Go back home"
        /&gt;
      );
    }
  }
  
  const styles = StyleSheet.create({
    icon: {
      width: 26,
      height: 26,
    },
  });
  
  const MyApp = TabNavigator({
    Displayed: {
      screen: MyHomeScreen,
    },
    Notifications: {
      screen: MyNotificationsScreen,
    },
  }, {
    tabBarOptions: {
      activeTintColor: '#e91e63',
    },
  });
  </code></pre>