App\Http\Controllers\EditorController::fileSource PHP Method

    public function fileSource(EditorHandler $handler, $instanceId, $id)
    {
        if (empty($id)) {
            throw new InvalidArgumentException();
        }
        $file = File::find($id);
        /** @var \Xpressengine\Media\MediaManager $mediaManager */
        $mediaManager = app('xe.media');
        if ($mediaManager->is($file) === true) {
            $dimension = 'L';
            if (\Agent::isMobile() === true) {
                $dimension = 'M';
            }
            $media = Image::getThumbnail($mediaManager->make($file), EditorHandler::THUMBNAIL_TYPE, $dimension);
            header('Content-type: ' . $media->mime);
            echo $media->getContent();
        }
    }