MVC C# จะแปลง WebImage ไปเป็น Byte เข้า Stream ยังไงครับ

        image = GetImageFromServer(@"..\Content\example.tif");
          
           
            //convert from tiff to png
            var tiffStream = new MemoryStream(image);
            var pngStream = new MemoryStream();
            Bitmap.FromStream(tiffStream).Save(pngStream, ImageFormat.Png);

      var  image1 = new WebImage(Server.MapPath(Path.Combine("~", imageUrl)));
            image1.AddTextWatermark("** DEMO ** ** DEMO ** ** DEMO ** ", fontSize: 30, fontColor: "White", horizontalAlign: "Center", verticalAlign: "Middle", opacity: 70);