怎么给图片加水印效果

//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; 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(".") + "/Alex.gif"); 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);