生成缩略图

 protected void btnUpdate_Click(object sender, EventArgs e)
        {
            int SPhotoMaxSize = 39;
            int BPhotoMaxSize = 160;

            Graphics g = null;
            System.Drawing.Image upimage = null;
            System.Drawing.Image thumimg = null;
            System.Drawing.Image simage = null;
            System.Drawing.Image bimage = null;

            Bitmap outputfile = null;

            string photoPath = "/mocktrade/userprofile/images/";
            string fileName = Guid.NewGuid().ToString();
            string extension = Path.GetExtension(FileUpload1.PostedFile.FileName).ToUpper();

            //原圖路徑               
            string bPath = photoPath + fileName + "_b" + extension;
            string sPath = photoPath + fileName + "_s" + extension;

            Regex re = new Regex(@"^(\.jpeg|\.jpg|\.gif|\.png|\.bmp)$", RegexOptions.IgnoreCase);

            if (re.IsMatch(extension))
            {
                try
                {
                    //BlogControl.DAL.BlogDataSetTwo.MT_USERPROFILERow userRow = _blogBll.GetMTUserProfileByUserName(OwnerUserName);
                    //if (userRow != null)
                    //{
                    int width, height, newwidth, newheight;
                    int bWidth, bHeight, bNewWidth, bNewHeight;
                    System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback); ;

                    //創建目錄
                    if (!Directory.Exists(resourcesPath + photoPath))
                        Directory.CreateDirectory(resourcesPath + photoPath);

                    //string simagefile = Server.MapPath("a8logo.jpg"); //要加水印的文件
                    upimage = System.Drawing.Image.FromStream(FileUpload1.PostedFile.InputStream); //上传的图片

                    width = upimage.Width;
                    height = upimage.Height;
                    bWidth = upimage.Width;
                    bHeight = upimage.Height;

                    //缩略图
                    if (width > height && width >= SPhotoMaxSize)
                    {
                        newwidth = SPhotoMaxSize;
                        newheight = (int)((double)height / (double)width * (double)newwidth);
                    }
                    else if (width < height && height >= SPhotoMaxSize)
                    {
                        newheight = SPhotoMaxSize;
                        newwidth = (int)((double)width / (double)height * (double)newheight);
                    }
                    else if (width == height && height >= SPhotoMaxSize)
                    {
                        newheight = SPhotoMaxSize;
                        newwidth = SPhotoMaxSize;
                    }
                    else
                    {
                        newwidth = width;
                        newheight = height;
                    }

                    //大图
                    if (bWidth > bHeight && bWidth >= BPhotoMaxSize)
                    {
                        bNewWidth = BPhotoMaxSize;
                        bNewHeight = (int)((double)bHeight / (double)bWidth * (double)bNewWidth);
                    }
                    else if (bWidth < bHeight && bHeight >= BPhotoMaxSize)
                    {
                        bNewHeight = BPhotoMaxSize;
                        bNewWidth = (int)((double)bWidth / (double)bHeight * (double)bNewHeight);
                    }
                    else if (bWidth == bHeight && bHeight >= BPhotoMaxSize)
                    {
                        bNewHeight = BPhotoMaxSize;
                        bNewWidth = BPhotoMaxSize;
                    }
                    else
                    {
                        bNewWidth = bWidth;
                        bNewHeight = bHeight;
                    }

                    thumimg = upimage.GetThumbnailImage(newwidth, newheight, callb, IntPtr.Zero);
                    bimage = upimage.GetThumbnailImage(bNewWidth, bNewHeight, callb, IntPtr.Zero);

                    outputfile = new Bitmap(upimage);

                    bimage.Save(resourcesPath + bPath);
                    thumimg.Save(resourcesPath + sPath);
                    outputfile.Dispose();

                    //刪除舊圖
                    Common.FileSystem.deleteFile(resourcesPath + BlogProfile.PHOTOPATH);
                    Common.FileSystem.deleteFile(resourcesPath + BlogProfile.THUMBNAILPATH);

                    //更新
                    _blogBll.UpdatePhoto(bPath, sPath, OwnerUserName);
                    //_UserProfileBLL.UpdateUserProfile(OwnerUserName, bPath, sPath, Common.CRGlobal.toDecimal(userRow.VOCATION), Common.CRGlobal.toDecimal(userRow.INVESTEXPERIENCE),
                    //    Common.CRGlobal.toDecimal(userRow.INTERESTITEM), Common.CRGlobal.toDecimal(userRow.INTERESTMARKET), Common.CRGlobal.toDecimal(userRow.STATUS));
                    //}

                    ShowDialog("提示", "上傳成功");
                    return;
                }
                catch
                {
                    ShowDialog("提示", "對不起！上傳失敗");
                    return;
                }
                finally
                {
                    if (g != null)
                        g.Dispose();
                    if (thumimg != null)
                        thumimg.Dispose();
                    if (upimage != null)
                        upimage.Dispose();
                    if (simage != null)
                        simage.Dispose();

                    FileUpload1.Dispose();

                    //重新绑定数据
                    BlogDataSet.BLOG_PROFILERow blogRow = this.BlogProfile;
                    //BlogControl.DAL.BlogDataSetTwo.MT_USERPROFILERow userRow = _blogBll.GetMTUserProfileByUserName(OwnerUserName);
                    //if (userRow != null)
                    //{
                    //string resourcesPath = Server.MapPath(Common.ResourcesPath.RootPath);
                    //Image1.ImageUrl = Common.ResourcesPath.RootPath + userRow.THUMBNAILPATH;
                    //Image1.ImageUrl = GetUrl(userRow.THUMBNAILPATH);
                    Image1.ImageUrl = GetUrl(BlogProfile.THUMBNAILPATH);
                    //}
                }
            }
            else
            {
                ShowDialog("提示", "對不起！只能上傳jpeg,jpg,gif,png,bmp圖片");
                return;
            }
        }