/// <summary>

   /// 为图片生成缩略图

   /// </summary>

   /// <param name="phyPath">原图片的路径</param>

   /// <param name="width">缩略图宽</param>

   /// <param name="height">缩略图高</param>

   /// <returns></returns>

   public System.Drawing.Image GetThumbnail(System.Drawing.Image image, int width, int height)

   {

       Bitmap bmp = new Bitmap(width, height);

       //从Bitmap创建一个System.Drawing.Graphics

       System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp);

       //设置

       gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

       //下面这个也设成高质量

       gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

       //下面这个设成High

       gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

       //把原始图像绘制成上面所设置宽高的缩小图

       System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(, , width, height);

       gr.DrawImage(image, rectDestination, , , image.Width, image.Height, GraphicsUnit.Pixel);

       return bmp;

   }

  HttpPostedFile file = photoFile.PostedFile;

        if (!file.ContentType.Contains("image"))

        {

　　　　　　return "照片格式不合法";

        }

        string ext = Path.GetExtension(file.FileName).ToLower();

        if (ext != ".jpg" && ext != ".gif" && ext != ".png" && ext != ".jpeg")

        {

　　　　　　return "请您上传jpg、gif、png图片";

        }

        if (file.ContentLength >  *  * )

        {

　　　　　　return "请您上传512字节内的图片";

        }

        string newName = Guid.NewGuid().ToString();

        string tempPath = "upload/";

        string img = tempPath + newName + ext;

        string filePath = Server.MapPath(img);

        if (!Directory.Exists(tempPath))

        {

            Directory.CreateDirectory(tempPath);

        }

        using (System.Drawing.Image originalImage = System.Drawing.Image.FromStream(file.InputStream))

        {

            GetThumbnail(originalImage, , ).Save(filePath);

        }