title: How to set small notification icons in react-native according to device resolution
body: <p>I'm receiving notifications and by now using default icons.
  I want to customize them, but I really got lost in time to set the icon.</p>
  
  <p>Using <a href="https://rnfirebase.io/docs/v4.2.x/notifications/reference/AndroidNotification" rel="nofollow noreferrer">react-native-firebase notifications</a>.</p>
  
  <p>I've already created right size icons with this online <a href="https://romannurik.github.io/AndroidAssetStudio/icons-notification.html#source.type=clipart&amp;source.clipart=ac_unit&amp;source.space.trim=1&amp;source.space.pad=0&amp;name=ic_stat_ac_unit" rel="nofollow noreferrer">notification icons generator</a>.</p>
  
  <p>Then I created the directories in the places and with correct names, like following (Android):</p>
  
  <pre><code>android/app/src/main/res/drawable-mdpi/ (24x24)
  
  android/app/src/main/res/drawable-hdpi/ (36x36)
  
  android/app/src/main/res/drawable-xhdpi/ (48x48)
  
  android/app/src/main/res/drawable-xxhdpi/ (72x72)
  
  android/app/src/main/res/drawable-xxxhdpi/ (96x96)
  </code></pre>
  
  <p>Now, I want to get the right sized image and resolve it here.</p>
  
  <pre><code>var notification = new firebase.notifications.Notification({
                    sound: 'default',
                    show_in_foreground: true,
               })
               .android.setPriority(firebase.notifications.Android.Priority.High)
               .android.setChannelId("channel")
               .android.setSmallIcon(  &lt;How do I put icon paths here?&gt;  ); 
  </code></pre>
  
  <p>I've read some docs and guidelines, but I'm really not having an idea.
  What is the right way to reference these paths?</p>