Resizing an image without losing the image quality in ASP.Net

private static System.Drawing.Image RezizeImage(System.Drawing.Image img, int maxWidth, int maxHeight)
    {
        if (img.Height < maxHeight && img.Width < maxWidth) return img;
        using (img)
        {
            Double xRatio = (double)img.Width / maxWidth;
            Double yRatio = (double)img.Height / maxHeight;
            Double ratio = Math.Max(xRatio, yRatio);
            int nnx = (int)Math.Floor(img.Width / ratio);
            int nny = (int)Math.Floor(img.Height / ratio);
            Bitmap cpy = new Bitmap(nnx, nny, PixelFormat.Format32bppArgb);
            using (Graphics gr = Graphics.FromImage(cpy))
            {
                gr.Clear(Color.Transparent);

                // This is said to give best quality when resizing images
                gr.InterpolationMode = InterpolationMode.HighQualityBicubic;

                gr.DrawImage(img,
                    new Rectangle(0, 0, nnx, nny),
                    new Rectangle(0, 0, img.Width, img.Height),
                    GraphicsUnit.Pixel);
            }
            return cpy;
        }

    }

    private static MemoryStream BytearrayToStream(byte[] arr)
    {
        return new MemoryStream(arr, 0, arr.Length);
    }

    public static void HandleImageUpload(string p_postedImageFileName, int width, int height, Stream toStream, string path)
    {
        FileStream fs = default(FileStream);
        string originalFileName = HttpContext.Current.Server.MapPath(path + p_postedImageFileName.Replace(" ", "").Replace("%20", ""));
        fs = new FileStream(originalFileName, FileMode.Open);
        BinaryReader br = new BinaryReader(fs);
        byte[] binaryImage = br.ReadBytes((int)fs.Length);
        br.Close();
        fs.Close();

        System.Drawing.Image img = RezizeImage(System.Drawing.Image.FromStream(BytearrayToStream(binaryImage)), width, height);
        img.Save(toStream, System.Drawing.Imaging.ImageFormat.Png);
    }