Reconnect to Wifi/Data after receiving GCM

Question

So my Android app uses GCM push notifications and implements a wakeful service to format the incoming notification. I am implementing corresponding avatar images for the notifications but the images are pulled from our server using REST.

My problem - if the app is not in the foreground (closed or disabled in standby mode) then I am unable to connect to retrieve the avatar resource. I have implemented my code from here: https://developer.android.com/google/gcm/client.html (under "Receive a message").

Question - how do I relaunch a closed app so that I can retrieve the avatar in order to add to the GCM notification?

Here is my snippet from when I create the notification:

    RestApi restApi = RestApi.getInstance(this);
    senderAvatarUrl = restApi.MyAppAvatarThumbnailUrl(id);
    bitmap = getBitmapFromURL(senderAvatarUrl);

    if (bitmap == null){
        bitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.placeholder_avatar);
    }

    bitmap = getCroppedBitmap(bitmap);

    mBuilder= new NotificationCompat.Builder(this).setAutoCancel(true)
                    .setSmallIcon(R.drawable.fourth_notification)
                    .setLargeIcon(bitmap)
                    .setContentTitle(nameShouldBe)
                    .setStyle(new NotificationCompat.BigTextStyle().bigText(msg))
                    .setLights(Color.GREEN, 100, 10000)
                    .setContentText(msg);

    mBuilder.build();

Thanks