Asp.net(C#)给图片加上水印效果

 1if (FileUpload1.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
 2        {
 3            FunctionUtility.JavaScriptHelper.Alert("上传的文件格式不正确！");
 4            return;
 5        }
 6
 7        Stream oStream = FileUpload1.PostedFile.InputStream;
 8        System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
 9
10        if(CheckBox1.Checked)
11        {
12            //加文字水印
13            Graphics g = Graphics.FromImage(oImage);
14            g.DrawImage(oImage, 0, 0, oImage.Width, oImage.Height);
15            Font f = new Font("Verdana",15);
16            Brush b = new SolidBrush(Color.White);
17            g.DrawString("http://www.itwealth.cn制作", f, b, 0, oImage.Height - 30);
18            g.Dispose();
19        }
20        else
21        {
22            //加图片水印
23            System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Server.MapPath("/DesignImages/Images/SYT/Admin.jpg"));
24            Graphics g = Graphics.FromImage(oImage);
25            g.DrawImage(copyImage, new Rectangle(oImage.Width - copyImage.Width, oImage.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
26            g.Dispose();
27        }
28
29        string setFileName = FunctionUtility.FileHelper.GetDateTimeFileName() + ".jpg";
30        string oFullName = Server.MapPath("/DesignImages/Images/SYT/" + setFileName);
31        oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
32        oImage.Dispose();
33
34        Image1.Visible = true;
35        Image1.ImageUrl = "/DesignImages/Images/SYT/" + setFileName;
36        FunctionUtility.JavaScriptHelper.Alert("水印加载成功！");