image Compresion and decompression

public void create_thumbnail(string filePath, string filename)

        {

            System.Drawing.Image image1 = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(filePath) + "\\" + filename);

            decimal width;

            float temp;

            temp = (float)image1.Height / (float)90;

            width = (decimal)((float)image1.Width / (float)temp);

            System.Drawing.Image thumbnailImage = image1.GetThumbnailImage((int)width, 90, new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero);

            MemoryStream imageStream = new MemoryStream();

            thumbnailImage.Save(imageStream, System.Drawing.Imaging.ImageFormat.Jpeg);

            byte[] imageContent = new Byte[imageStream.Length];

            imageStream.Position = 0;

            imageStream.Read(imageContent, 0, (int)imageStream.Length);

            //string fileP = filePath.Replace("ThumbNail", "");

            Stream stream = new FileStream(HttpContext.Current.Server.MapPath(filePath + "/ThumbNail/") + "\\" + filename, FileMode.Create);

            stream.Write(imageContent, 0, imageContent.Length);

            stream.Close();

            //image1.Dispose();

        }

        private bool ThumbnailCallback()

        {

            return true;

        }