/// <summary>

        /// 在一张图片的指定位置处加入一张具有水印效果的图片

        /// </summary>

        /// <param name="SourceImage">指定源图片的绝对路径</param>

        /// <param name="WaterMarkImage">指定水印图片的绝对路径</param>

        /// <param name="SaveImage">保存图片的绝对路径</param>

        public static void MakeWaterMark(string SourceImage, string WaterMarkImage, string SaveImage)

        {

            // 创建一个对象用于操作需要加水印的源图片

            Image imgPhoto = Image.FromFile(SourceImage);

            // 获取该源图片的宽度和高度

            int phWidth = imgPhoto.Width;

            int phHeight = imgPhoto.Height;

            // 创建一个BMP格式的空白图片(宽度和高度与源图片一致)

            Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);

            // 设置该新建空白BMP图片的分辨率

            bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            // 将该BMP图片设置成一个图形对象

            Graphics grPhoto = Graphics.FromImage(bmPhoto);

            // 设置生成图片的质量

            grPhoto.SmoothingMode = SmoothingMode.AntiAlias;

            // 将源图片加载至新建的BMP图片中

            grPhoto.DrawImage(

                imgPhoto,                               // Photo Image object

                new Rectangle(, , phWidth, phHeight), // Rectangle structure

                ,                                      // x-coordinate of the portion of the source image to draw.

                ,                                      // y-coordinate of the portion of the source image to draw.

                phWidth,                                // Width of the portion of the source image to draw.

                phHeight,                               // Height of the portion of the source image to draw.

                GraphicsUnit.Pixel);                    // Units of measure 

            // 创建水印图片的 Image 对象

            Image imgWatermark = new Bitmap(WaterMarkImage);

            // 获取水印图片的宽度和高度

            int wmWidth = imgWatermark.Width;

            int wmHeight = imgWatermark.Height;

            //------------------------------------------------------------

            // 第一步： 插入水印图片

            //------------------------------------------------------------

            //Create a Bitmap based on the previously modified photograph Bitmap

            Bitmap bmWatermark = new Bitmap(bmPhoto);

            bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            //Load this Bitmap into a new Graphic Object

            Graphics grWatermark = Graphics.FromImage(bmWatermark);

            //To achieve a transulcent watermark we will apply (2) color

            //manipulations by defineing a ImageAttributes object and

            //seting (2) of its properties.

            ImageAttributes imageAttributes = new ImageAttributes();

            //The first step in manipulating the watermark image is to replace

            //the background color with one that is trasparent (Alpha=0, R=0, G=0, B=0)

            //to do this we will use a Colormap and use this to define a RemapTable

            ColorMap colorMap = new ColorMap();

            //My watermark was defined with a background of 100% Green this will

            //be the color we search for and replace with transparency

            colorMap.OldColor = Color.FromArgb(, , , );

            colorMap.NewColor = Color.FromArgb(, , , );

            ColorMap[] remapTable = { colorMap };

            imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

            //The second color manipulation is used to change the opacity of the

            //watermark.  This is done by applying a 5x5 matrix that contains the

            //coordinates for the RGBA space.  By setting the 3rd row and 3rd column

            //to 0.3f we achive a level of opacity

            float[][] colorMatrixElements = {

                                                new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},

                                                new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},

                                                new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},

                                                new float[] {0.0f,  0.0f,  0.0f,  0.3f, 0.0f},

                                                new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}

                                            };

            ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default,

                ColorAdjustType.Bitmap);

            //For this example we will place the watermark in the upper right

            //hand corner of the photograph. offset down 10 pixels and to the

            //left 10 pixles

            int xPosOfWm = ((phWidth - wmWidth) - );

            int yPosOfWm = ;

            grWatermark.DrawImage(imgWatermark,

                new Rectangle(xPosOfWm, yPosOfWm, wmWidth, wmHeight),  //Set the detination Position

                ,                  // x-coordinate of the portion of the source image to draw.

                ,                  // y-coordinate of the portion of the source image to draw.

                wmWidth,            // Watermark Width

                wmHeight,            // Watermark Height

                GraphicsUnit.Pixel, // Unit of measurment

                imageAttributes);   //ImageAttributes Object

            //Replace the original photgraphs bitmap with the new Bitmap

            imgPhoto.Dispose();

            imgPhoto = bmWatermark;

            grPhoto.Dispose();

            grWatermark.Dispose();

            bmPhoto.Dispose();

            //------------------------------------------------------------

            // 第三步：保存图片

            //------------------------------------------------------------

            imgPhoto.Save(SaveImage, ImageFormat.Jpeg);

            // 释放使用中的资源

            imgPhoto.Dispose();

            imgWatermark.Dispose();

            bmWatermark.Dispose();

        }