Firebase Expandable Notification Show image when app is in background

Question

I am implementing FCM notifications in Android, but how does notifications differ depending on the app status (background vs. foreground)?

Answer 1

Send Big Picture notification from Firebase console : Works for both background and foreground app

Instead of onMessageReceived, override zzm() of FirebaseMessagingService and create your custom notification from here

@Override
public void zzm(Intent intent) {
    Log.e(TAG, "zzm : " + intent);
    createBigPictureNotification();        
}

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {

}