Asp.net(C#)给图片加上水印效果

        

        private const string personPicture = "~/images/users/";//存放图片的文件夹
        private string watermarkUrl = "~/Images/users/watermark.png";//水印图片
        private string defaultImageUrl = "~/Images/users/noperson.jpg";//若无图片则显示一张默认的

 

        //上传用户照片
        private void fileUpload(FileUpload fileUpload)
        {
            if (fileUpload.PostedFile != null)
            {
                //执行上传用户照片操作
                int fileSize = fileUpload.PostedFile.ContentLength;//得到上传文件大小
                byte[] arrFile = new byte[fileSize];//把文件大小转换成二进制数组
                if (fileSize > 0)
                {
                    string[] getFileType = fileUpload.FileName.Split('.');
                    string imageName = getFileType[0].ToString();//得到文件名称部分
                    string suffix = getFileType[1].ToString();//得到文件后缀部分

                    Stream streamReader = fileUpload.PostedFile.InputStream;
                    streamReader.Read(arrFile, 0, fileSize);

                    //指定要上传到的文件虚拟路径
                    string dummyPath = personPicture + txtUserId.Text.Trim() + "." + suffix;

                    //得到文件上传的物理路径
                    string phyPath = Request.MapPath(dummyPath);

                    if (System.IO.File.Exists(phyPath))
                    {
                        System.IO.File.Delete(phyPath);
                    }
                    //给上传的照片添加水印
                    System.Drawing.Image image = System.Drawing.Image.FromStream(streamReader);
                    System.Drawing.Image watermark = System.Drawing.Image.FromFile(Request.MapPath(watermarkUrl));
                    Graphics g = Graphics.FromImage(image);
                    g.DrawImage(watermark, new Rectangle(image.Width - watermark.Width, image.Height - watermark.Height, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel);
                    g.Dispose();
                    //保存图片
                    image.Save(phyPath);
                }
            }
        }

        以上代码是我从自己的项目中摘取的，如有不足之处请多提宝贵意见。