生成缩略图[该文从优快云论坛中提取而来] 献给我自己,也献给不会的园子里的朋友...

// <summary>
  /// 生成缩略图
  /// </summary>
  /// <param name="fileName">原文件</param>
  /// <param name="width">宽度</param>
  /// <param name="height">高度</param>
  private void CreateThumbnailImage(string fileName, string smallPath, int width, int height)
  {
  //版权信息
  string strAdd = "www.wander.com";
  //生成的缩略图的名字=年月日+文件大小(防止文件名相同)
  string newFileName = smallPath;

  System.Drawing.Image image, newImage;
  //载入原图像
  image = System.Drawing.Image.FromFile(Server.MapPath(fileName));
  //回调
  System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(callBack);
  //生成缩略图
  newImage = image.GetThumbnailImage(width, height, callb, new System.IntPtr()); AddInfo(newImage, strAdd, newFileName, 16);

  image.Dispose();
  newImage.Dispose();

  Image1.ImageUrl = newFileName;
  }

  /// <summary>
  /// 添加版权信息
  /// </summary>
  /// <param name="image"></param>
  /// <param name="strAdd"></param>
  /// <param name="newFileName"></param>
  /// <param name="fontSize"></param>
  private void AddInfo(System.Drawing.Image image, string strAdd, string newFileName, int fontSize)
  {
  Response.Clear();
  Bitmap b = new Bitmap(image);
  Graphics g = Graphics.FromImage(b);
  g.DrawString(strAdd, new Font("宋体", fontSize), new SolidBrush(Color.Red), image.Width / 2 - 80, image.Height - 30);
  b.Save(Server.MapPath(newFileName), System.Drawing.Imaging.ImageFormat.Gif);
  }

  private bool callBack()
  {
  return true;
  }

  protected void Button1_Click(object sender, EventArgs e)
  {
  if (loadFile.PostedFile != null)
  {
  //判断是不是图像文件
  if (loadFile.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
  {
  //文件类型错误
  }
  else
  {
  string ext = loadFile.PostedFile.FileName.Substring(loadFile.PostedFile.FileName.LastIndexOf("."));
  //生成新的原文件名 年月日+文件大小+扩展名
  string path = "Uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + ext;
  //加上版权信息的文件
  string newPath = "Uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + "new" + ext;
  //缩略图文件名
  string newFileName = "uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + "small.gif";
  //上传原图
  loadFile.PostedFile.SaveAs(Server.MapPath(path));
  //生成缩略图
  CreateThumbnailImage(path, newFileName, 200, 300);

  //给原图加上版权信息
  System.Drawing.Image image = System.Drawing.Image.FromFile(Server.MapPath(path));
  AddInfo(image, "www.wander.com", newPath, 20);
  image.Dispose();
  }
  }

  }

转载于:https://www.cnblogs.com/qingci/archive/2011/03/14/1984025.html