I'm trying to create a multi page tiff from 2 seperate tiffs:

public static void AppendToTiff(string TargetTiff, string TiffToAdd)
{
    Image img1 = Image.FromFile(TargetTiff);
    Image img2 = Image.FromFile(TiffToAdd);
    int Height = img1.Height + img2.Height;
    int Width = img1.Width;

    string path = Path.GetDirectoryName(TargetTiff);
    string tempfile = path + "\\" + Path.GetFileNameWithoutExtension(Path.GetTempFileName()) + ".tiff";

    using (Bitmap newImg = new Bitmap(Width, Height))
    {
        Graphics g = Graphics.FromImage(newImg);
        g.DrawImage(img1, 0, 0);
        g.DrawImage(img2, 0, Height);
        g.Save();
        newImg.Save(tempfile);
    }
}

The result is one tiff, the correct size, but with only the first image showing at the top. Anyone know how to do this?