asp.net 给图片添加水印

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
using System.Drawing;

public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button1_Click(object sender, EventArgs e)
{
if (UploadFile.PostedFile.FileName.Trim() != "")
{
//上传文件
string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToUpper();
string fileName = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + DateTime.Now.Day.ToString() + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString();
string path = Server.MapPath(".") + "/UploadFile/" + fileName + extension;//上传要加水印的图片
UploadFile.PostedFile.SaveAs(path);

//加文字水印，注意，这里的代码和以下加图片水印的代码不能共存
//System.Drawing.Image image = System.Drawing.Image.FromFile(path);
//Graphics g = Graphics.FromImage(image);
//g.DrawImage(image, 0, 0, image.Width, image.Height);
//Font f = new Font("Verdana", 32);
//Brush b = new SolidBrush(Color.White);
//string addText = AddText.Value.Trim();
//g.DrawString(addText, f, b, 10, 10);
//g.Dispose();

//加图片水印
System.Drawing.Image image = System.Drawing.Image.FromFile(path);
System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Server.MapPath(".") + "/UploadFile/register.jpg");//添加的图片水印
Graphics g = Graphics.FromImage(image);
g.DrawImage(copyImage, new Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
g.Dispose();

//保存加水印过后的图片,删除原始图片
string newPath = Server.MapPath(".") + "/UploadFile/" + fileName + "_new" + extension;
image.Save(newPath);
image.Dispose();
if (File.Exists(path))
{
File.Delete(path);
}
Response.Redirect(newPath);
}

}
}