private async Task LoadImage(int imageNumber = 0) //load image to wpf
        {
            var comic = await ComicProcessor.LoadComicAsync(imageNumber);

            if (imageNumber == 0)
            {
                maxNumber = comic.Num;
            }
            currentNumber = comic.Num;

            var uri = new Uri(comic.Img);

            comicImage.Source = new BitmapImage(uri);
        }