A generic error occurred in GDI+.

protected void btnCrop_Click(object sender, EventArgs e)
        {
            string ImageName = Session["pic"].ToString();
            int x = Convert.ToInt32(X.Value);
            int y = Convert.ToInt32(Y.Value);
            int w = Convert.ToInt32(W.Value);
            int h = Convert.ToInt32(H.Value);
            double ratio = 0;
            //int w1 = int.Parse(imgCrop.Width.Value.ToString());
            double w1 = double.Parse(Session["width"].ToString());
            ratio = (w1 / 400.0);
            double w12 = w * ratio;
            double h12 = h * ratio;
            double x1 = x * ratio;
            double y1 = y * ratio;
            int wm = int.Parse(Math.Round(w12).ToString());
            int hm = int.Parse(Math.Round(h12).ToString());
            int xm = int.Parse(Math.Round(x1).ToString());
            int ym = int.Parse(Math.Round(y1).ToString());
            double imgratio = w12 / h12;
            string pathcrop = "";
            byte[] CropImage = Crop(path + Session["pic"].ToString(), w, h, x, y);
            using (MemoryStream ms = new MemoryStream(CropImage, 0, CropImage.Length))
            {
                ms.Write(CropImage, 0, CropImage.Length);
                using (SD.Image CroppedImage = SD.Image.FromStream(ms, true))
                {
                    string SaveTo = path1 + Session["pic"].ToString();
                    CroppedImage.Save(SaveTo, CroppedImage.RawFormat);
                    pnlCrop.Visible = false;
                    pnlCropped.Visible = true;
                    imgCropped.ImageUrl = "Admin/ProductImage/Product/Cropped/" + Session["pic"].ToString();
                    pathcrop = path1 + Session["pic"].ToString();
                    //Response.Redirect("crop.aspx?act=crop");
                    //ScriptManager.RegisterStartupScript(Page, typeof(Page), "OpenWindow", "window.open('crop.aspx?act=crop');", true);
                }
            }
            try
            {
                Size thnmb = new Size();
                double height = (168.0 / imgratio);
                //thnmb.Height = 142;
                thnmb.Width = 168;
                thnmb.Height = int.Parse(Math.Round(height).ToString());
                double hbig = (392.0 / imgratio);
                Size big = new Size();
                big.Width = 392;
                // big.Height = 391;
                big.Height = int.Parse(Math.Round(hbig).ToString());
                Size zoom = new Size();
                zoom.Width = 600;
                zoom.Height = 600;
                string pathbig = "/Admin/ProductImage/Product/Big/" + Session["pic"].ToString();
                string paththumb = "/Admin/ProductImage/Product/Thumb/" + Session["pic"].ToString();
                string pathzoom = "/Admin/ProductImage/Product/Zoom/" + Session["pic"].ToString();
                string path5 = Request.PhysicalApplicationPath + "Admin\\ProductImage\\Product\\Cropped\\" + Session["pic"].ToString();
                string path4 = Request.PhysicalApplicationPath;

                //Common.resizeImage(System.Drawing.Image.FromFile(path5), big).Save(HttpContext.Current.Request.PhysicalApplicationPath + "Admin\\ProductImage\\Product\\Big\\" + Session["pic"].ToString());
                //Common.resizeImage(System.Drawing.Image.FromFile(path5), thnmb).Save(HttpContext.Current.Request.PhysicalApplicationPath + "Admin\\ProductImage\\Product\\Thumb\\" + Session["pic"].ToString());
                //Common.resizeImage(System.Drawing.Image.FromFile(path5), zoom).Save(HttpContext.Current.Request.PhysicalApplicationPath + "Admin\\ProductImage\\Product\\Zoom\\" + Session["pic"].ToString());
                Common.resizeImage(System.Drawing.Image.FromFile(path5), big).Save(path4 + "Admin\\ProductImage\\Product\\Big\\" + Session["pic"].ToString());
                Common.resizeImage(System.Drawing.Image.FromFile(path5), thnmb).Save(path4 + "Admin\\ProductImage\\Product\\Thumb\\" + Session["pic"].ToString());
                Common.resizeImage(System.Drawing.Image.FromFile(path5), zoom).Save(path4 + "Admin\\ProductImage\\Product\\Zoom\\" + Session["pic"].ToString());
                con.cmdmain.Parameters.AddWithValue("@imgthumb", paththumb);
                con.cmdmain.Parameters.AddWithValue("@imgbig", pathbig);
                con.cmdmain.Parameters.AddWithValue("@imgzoom", pathzoom);
                con.cmdnonquery("update product set pic=@imgthumb,pic_big=@imgbig,pic_zoom=@imgzoom where productid='" + Request["pid"] + "'");
                con.cmdmain.Parameters.AddWithValue("@pid", Request["pid"]);
                con.cmdnonquery("insert into product_images(pid,pic,picbig,piczoom) values(@pid,@imgthumb,@imgbig,@imgzoom)");
                pnlCrop.Visible = false;
                pnlCropped.Visible = true;
                imgCropped.ImageUrl = "Admin/ProductImage/Product/Cropped/" + Session["pic"].ToString();
                Response.Write("<script>alert('Item Cropped Successfully!!')</script>");
                Response.Redirect("ProductList.aspx");
            }
            catch (Exception ex)
            {
                Response.Write("some technical problem");
            }
            //lnkcrop.Visible = false;
           //lnkproceed.Visible = true;
        }