C#

protected void btnsave_Click(object sender, EventArgs e)
        {
            string filename = Path.GetFileName(fileupload1.PostedFile.FileName);
            string targetPath = Server.MapPath("Images/" + filename);
            Stream strm = fileupload1.PostedFile.InputStream;
            var targetFile = targetPath;
            //Based on scalefactor image size will vary
            GenerateThumbnails(0.5, strm, targetFile);
            BindDataList();
        }
    
private void GenerateThumbnails(double scaleFactor, Stream sourcePath,string targetPath)
        {
            using (var image = System.Drawing.Image.FromStream(sourcePath))
            {
                // can given width of image as we want
                var newWidth = (int)(image.Width * scaleFactor);
                // can given height of image as we want
                var newHeight = (int)(image.Height * scaleFactor);
                var thumbnailImg = new Bitmap(newWidth, newHeight);
                var thumbGraph = Graphics.FromImage(thumbnailImg);

                thumbGraph.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                thumbGraph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                thumbGraph.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                var imageRectangle = new Rectangle(0, 0, newWidth, newHeight);
                thumbGraph.DrawImage(image, imageRectangle);
                thumbnailImg.Save(targetPath, image.RawFormat);
            }
        }
protected void BindDataList()
        {
            DirectoryInfo dir = new DirectoryInfo(MapPath("~/Images"));
            FileInfo[] files = dir.GetFiles();
            ArrayList listItems = new ArrayList();
            foreach (FileInfo info in files)
            {
                listItems.Add(info);
            }
            dtlist.DataSource = listItems;
            dtlist.DataBind();
        }