给图片添加图片水印[可按位置，水印图上放大缩小]

/// <summary>
        /// 给图片添加图片水印[可按位置，水印图上放大缩小]
        /// </summary>
        /// <param name="ImgFile">原图文件地址</param>
        /// <param name="WaterImg">水印图片地址</param>
        /// <param name="sImgPath">水印图片保存地址</param>
        /// <param name="Alpha">水印透明度设置</param>
        /// <param name="width">水印图片的宽度</param>
        /// <param name="height">水印图片的高度</param>
        /// <param name="bScale">水印图片是否按比例放大缩小</param>
        /// <param name="left">水印图片距左边</param>
        /// <param name="top">水印图片距上边</param>
        public static bool ImgWater(string ImgFile, string WaterImg, string sImgPath, float Alpha, int width,int height,bool bScale,int left,int top)//, int intDistance)
        {
            try
            {
                //装载图片
                FileStream fs = new FileStream(ImgFile, FileMode.Open);
                BinaryReader br = new BinaryReader(fs);
                byte[] bytes = br.ReadBytes((int)fs.Length);
                br.Close();
                fs.Close();
                MemoryStream ms = new MemoryStream(bytes);

                System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);
                int imgPhotoWidth = imgPhoto.Width;
                int imgPhotoHeight = imgPhoto.Height;

                System.Drawing.Image imgWatermark = new Bitmap(WaterImg);
                int imgWatermarkWidth = imgWatermark.Width;
                int imgWatermarkHeight = imgWatermark.Height;

                ////设置比例
                if(bScale)
                    height = width * imgWatermarkHeight / imgWatermarkWidth;
                //int imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                //int imgWatermarkHeightNew = Convert.ToInt32((imgPhotoWidth * aScale / imgWatermarkWidth) * imgWatermarkHeight);

                //将原图画出来
                Bitmap bmPhoto = new Bitmap(imgPhotoWidth, imgPhotoHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                bmPhoto.SetResolution(72, 72);
                Graphics gbmPhoto = Graphics.FromImage(bmPhoto);

                gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                gbmPhoto.Clear(Color.White);
                gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight), 0, 0, imgPhotoWidth, imgPhotoHeight, GraphicsUnit.Pixel);

                Bitmap bmWatermark = new Bitmap(bmPhoto);
                bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

                Graphics gWatermark = Graphics.FromImage(bmWatermark);

                //指定高质量显示水印图片质量
                gWatermark.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gWatermark.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                System.Drawing.Imaging.ImageAttributes imageAttributes = new System.Drawing.Imaging.ImageAttributes();

                //设置两种颜色,达到合成效果
                System.Drawing.Imaging.ColorMap colorMap = new System.Drawing.Imaging.ColorMap();
                colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

                System.Drawing.Imaging.ColorMap[] remapTable = { colorMap };

                imageAttributes.SetRemapTable(remapTable, System.Drawing.Imaging.ColorAdjustType.Bitmap);

                //用矩阵设置水印图片透明度
                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,  Alpha, 0.0f},
                   new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
                };

                System.Drawing.Imaging.ColorMatrix wmColorMatrix = new System.Drawing.Imaging.ColorMatrix(colorMatrixElements);
                imageAttributes.SetColorMatrix(wmColorMatrix, System.Drawing.Imaging.ColorMatrixFlag.Default, System.Drawing.Imaging.ColorAdjustType.Bitmap);

                //确定水印边距
                //int xPos = imgPhotoWidth - width;
                //int yPos = imgPhotoHeight - height;
                //int xPosOfWm = 0;
                //int yPosOfWm = 0;

                //if (xPos > intDistance)
                //    xPosOfWm = xPos - intDistance;
                //else
                //    xPosOfWm = xPos;

                //if (yPos > intDistance)
                //    yPosOfWm = yPos - intDistance;
                //else
                //    yPosOfWm = yPos;

                gWatermark.DrawImage(imgWatermark, new Rectangle(left, top, width, height), 0, 0, imgWatermarkWidth, imgWatermarkHeight, GraphicsUnit.Pixel, imageAttributes);
                imgPhoto = bmWatermark;
                imgPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

                //销毁对象
                gbmPhoto.Dispose();
                gWatermark.Dispose();

                imgPhoto.Dispose();
                imgWatermark.Dispose();

                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

其它的。

/// <summary>
        /// 图片水印
        /// </summary>
        /// <param name="ImgFile">原图文件地址</param>
        /// <param name="WaterImg">水印图片地址</param>
        /// <param name="sImgPath">水印图片保存地址</param>
        /// <param name="Alpha">水印透明度设置</param>
        /// <param name="iScale">水印图片在原图上的显示比例(水平)</param>
        /// <param name="intDistance">水印图片在原图上的边距确定,以图片的右边和下边为准,当设定的边距超过一定大小后参数会自动失效[0.4f-0.2f]</param>
        public static bool ImgWater(string ImgFile, string WaterImg, string sImgPath, float Alpha, float iScale, int intDistance)
        {
            try
            {
                //装载图片
                FileStream fs = new FileStream(ImgFile, FileMode.Open);
                BinaryReader br = new BinaryReader(fs);
                byte[] bytes = br.ReadBytes((int)fs.Length);
                br.Close();
                fs.Close();
                MemoryStream ms = new MemoryStream(bytes);

                System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);
                int imgPhotoWidth = imgPhoto.Width;
                int imgPhotoHeight = imgPhoto.Height;

                System.Drawing.Image imgWatermark = new Bitmap(WaterImg);
                int imgWatermarkWidth = imgWatermark.Width;
                int imgWatermarkHeight = imgWatermark.Height;


                //计算水印图片尺寸
                decimal aScale = Convert.ToDecimal(iScale);
                decimal pScale = 0.05M;
                decimal MinScale = aScale - pScale;
                decimal MaxScale = aScale + pScale;

                //设置比例
                int imgWatermarkWidthNew = Convert.ToInt32(imgPhotoWidth * aScale);
                int imgWatermarkHeightNew = Convert.ToInt32((imgPhotoWidth * aScale / imgWatermarkWidth) * imgWatermarkHeight);


                //将原图画出来
                Bitmap bmPhoto = new Bitmap(imgPhotoWidth, imgPhotoHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                bmPhoto.SetResolution(72, 72);
                Graphics gbmPhoto = Graphics.FromImage(bmPhoto);

                gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                gbmPhoto.Clear(Color.White);
                gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight), 0, 0, imgPhotoWidth, imgPhotoHeight, GraphicsUnit.Pixel);

                Bitmap bmWatermark = new Bitmap(bmPhoto);
                bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

                Graphics gWatermark = Graphics.FromImage(bmWatermark);

                //指定高质量显示水印图片质量
                gWatermark.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gWatermark.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                System.Drawing.Imaging.ImageAttributes imageAttributes = new System.Drawing.Imaging.ImageAttributes();

                //设置两种颜色,达到合成效果
                System.Drawing.Imaging.ColorMap colorMap = new System.Drawing.Imaging.ColorMap();
                colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

                System.Drawing.Imaging.ColorMap[] remapTable = { colorMap };

                imageAttributes.SetRemapTable(remapTable, System.Drawing.Imaging.ColorAdjustType.Bitmap);

                //用矩阵设置水印图片透明度
                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,  Alpha, 0.0f},
               new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
            };

                System.Drawing.Imaging.ColorMatrix wmColorMatrix = new System.Drawing.Imaging.ColorMatrix(colorMatrixElements);
                imageAttributes.SetColorMatrix(wmColorMatrix, System.Drawing.Imaging.ColorMatrixFlag.Default, System.Drawing.Imaging.ColorAdjustType.Bitmap);

                //确定水印边距
                int xPos = imgPhotoWidth - imgWatermarkWidthNew;
                int yPos = imgPhotoHeight - imgWatermarkHeightNew;
                int xPosOfWm = 0;
                int yPosOfWm = 0;

                if (xPos > intDistance)
                    xPosOfWm = xPos - intDistance;
                else
                    xPosOfWm = xPos;

                if (yPos > intDistance)
                    yPosOfWm = yPos - intDistance;
                else
                    yPosOfWm = yPos;

                gWatermark.DrawImage(imgWatermark, new Rectangle(xPosOfWm, yPosOfWm, imgWatermarkWidthNew, imgWatermarkHeightNew), 0, 0, imgWatermarkWidth, imgWatermarkHeight, GraphicsUnit.Pixel, imageAttributes);

                imgPhoto = bmWatermark;


                imgPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

                //销毁对象
                gbmPhoto.Dispose();
                gWatermark.Dispose();

                imgPhoto.Dispose();
                imgWatermark.Dispose();

                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 文字水印
        /// </summary>
        /// <param name="ImgFile">原图文件地址</param>
        /// <param name="TextFont">水印文字</param>
        /// <param name="sImgPath">文字水印图片保存地址</param>
        /// <param name="Alpha">文字透明度 其数值的范围在0到255</param>
        /// <param name="widthFont">文字块在图片中所占宽度比例</param>
        /// <param name="hScale">高度位置</param>
        public bool TextWater(string ImgFile, string TextFont, string sImgPath, int Alpha, float widthFont, float hScale)
        {
            try
            {
                FileStream fs = new FileStream(ImgFile, FileMode.Open);
                BinaryReader br = new BinaryReader(fs);
                byte[] bytes = br.ReadBytes((int)fs.Length);
                br.Close();
                fs.Close();
                MemoryStream ms = new MemoryStream(bytes);

                System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);
                int imgPhotoWidth = imgPhoto.Width;
                int imgPhotoHeight = imgPhoto.Height;

                Bitmap bmPhoto = new Bitmap(imgPhotoWidth, imgPhotoHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                bmPhoto.SetResolution(72, 72);
                Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
                gbmPhoto.Clear(Color.FromName("white"));//gif背景色
                gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight), 0, 0, imgPhotoWidth, imgPhotoHeight, GraphicsUnit.Pixel);

                //建立字体大小的数组,循环找出适合图片的水印字体
                int[] sizes = new int[] { 1000, 800, 700, 650, 600, 560, 540, 500, 450, 400, 380, 360, 340, 320, 300, 280, 260, 240, 220, 200, 180, 160, 140, 120, 100, 80, 72, 64, 48, 32, 28, 26, 24, 20, 28, 16, 14, 12, 10, 8, 6, 4, 2 };
                System.Drawing.Font crFont = null;
                System.Drawing.SizeF crSize = new SizeF();
                for (int i = 0; i < 43; i++)
                {
                    crFont = new Font("arial", sizes[i], FontStyle.Bold);
                    crSize = gbmPhoto.MeasureString(TextFont, crFont);

                    if ((ushort)crSize.Width < (ushort)imgPhotoWidth * widthFont)
                        break;
                }

                //设置水印字体的位置
                int yPixlesFromBottom = (int)(imgPhotoHeight * hScale);
                float yPosFromBottom = ((imgPhotoHeight - yPixlesFromBottom) - (crSize.Height / 2));
                float xCenterOfImg = (imgPhotoWidth * 1 / 2);

                System.Drawing.StringFormat StrFormat = new System.Drawing.StringFormat();
                StrFormat.Alignment = System.Drawing.StringAlignment.Center;

                //画两次制造透明效果
                System.Drawing.SolidBrush semiTransBrush2 = new System.Drawing.SolidBrush(Color.FromArgb(Alpha, 0, 0, 0));
                gbmPhoto.DrawString(TextFont, crFont, semiTransBrush2, new System.Drawing.PointF(xCenterOfImg + 1, yPosFromBottom + 1), StrFormat);

                System.Drawing.SolidBrush semiTransBrush = new System.Drawing.SolidBrush(Color.FromArgb(Alpha, 255, 255, 255));
                gbmPhoto.DrawString(TextFont, crFont, semiTransBrush, new System.Drawing.PointF(xCenterOfImg, yPosFromBottom), StrFormat);

                bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

                gbmPhoto.Dispose();
                imgPhoto.Dispose();
                bmPhoto.Dispose();

                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 缩略图
        /// </summary>
        /// <param name="ImgFile">原图文件地址</param>
        /// <param name="sImgPath">缩略图保存地址</param>
        /// <param name="ResizeWidth">缩略图宽度</param>
        /// <param name="ResizeHeight">缩略图高度</param>
        /// <param name="BgColor">缩略图背景颜色,注意,背景颜色只能指定KnownColor中的值,如white,blue,red,green等</param>
        public bool ResizeImg(string ImgFile, string sImgPath, int ResizeWidth, int ResizeHeight, string BgColor)
        {
            try
            {
                FileStream fs = new FileStream(ImgFile, FileMode.Open);
                BinaryReader br = new BinaryReader(fs);
                byte[] bytes = br.ReadBytes((int)fs.Length);
                br.Close();
                fs.Close();
                MemoryStream ms = new MemoryStream(bytes);

                System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);
                int imgPhotoWidth = imgPhoto.Width;
                int imgPhotoHeight = imgPhoto.Height;
                int StartX = 0;
                int StartY = 0;
                int NewWidth = imgPhotoWidth;
                int NewHeight = imgPhotoHeight;

                //计算缩放图片尺寸
                if (NewWidth > ResizeWidth)
                {
                    NewWidth = ResizeWidth;
                    NewHeight = Convert.ToInt32(imgPhotoHeight * Math.Round(Convert.ToDecimal(NewWidth) / Convert.ToDecimal(imgPhotoWidth), 10));
                }

                if (NewHeight > ResizeHeight)
                {
                    NewHeight = ResizeHeight;
                    NewWidth = Convert.ToInt32(imgPhotoWidth * Math.Round(Convert.ToDecimal(NewHeight) / Convert.ToDecimal(imgPhotoHeight), 10));
                }

                StartX = ResizeWidth - NewWidth;
                StartY = ResizeHeight - NewHeight;

                StartX = StartX > 0 ? StartX / 2 : 0;
                StartY = StartY > 0 ? StartY / 2 : 0;

                Bitmap bmPhoto = new Bitmap(ResizeWidth, ResizeHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                bmPhoto.SetResolution(72, 72);
                Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
                gbmPhoto.Clear(Color.FromName(BgColor));
                gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

                gbmPhoto.DrawImage(imgPhoto, new Rectangle(StartX, StartY, NewWidth, NewHeight), new Rectangle(0, 0, imgPhotoWidth, imgPhotoHeight), GraphicsUnit.Pixel);
                bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

                imgPhoto.Dispose();
                gbmPhoto.Dispose();
                bmPhoto.Dispose();

                return true;
            }
            catch (Exception err)
            {
                return false;
            }
        }

        /// <summary>
        /// 图片剪切
        /// </summary>
        /// <param name="ImgFile">原图文件地址</param>
        /// <param name="sImgPath">缩略图保存地址</param>
        /// <param name="PointX">剪切起始点 X坐标</param>
        /// <param name="PointY">剪切起始点 Y坐标</param>
        /// <param name="CutWidth">剪切宽度</param>
        /// <param name="CutHeight">剪切高度</param>
        public bool CutImg(string ImgFile, string sImgPath, int PointX, int PointY, int CutWidth, int CutHeight)
        {
            try
            {
                FileStream fs = new FileStream(ImgFile, FileMode.Open);
                BinaryReader br = new BinaryReader(fs);
                byte[] bytes = br.ReadBytes((int)fs.Length);
                br.Close();
                fs.Close();
                MemoryStream ms = new MemoryStream(bytes);
                System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(ms);

                //System.Drawing.Image imgPhoto = System.Drawing.Image.FromFile(ImgFile);
                //此处只能用filestream，用 System.Drawing.Image则会报多过进程访问文件的错误，会锁定文件
                Bitmap bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                bmPhoto.SetResolution(72, 72);
                Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
                gbmPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                gbmPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

                gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, CutWidth, CutHeight), new Rectangle(PointX, PointY, CutHeight, CutHeight), GraphicsUnit.Pixel);
                bmPhoto.Save(sImgPath, System.Drawing.Imaging.ImageFormat.Jpeg);

                imgPhoto.Dispose();
                gbmPhoto.Dispose();
                bmPhoto.Dispose();

                return true;
            }
            catch (Exception err)
            {
                return false;
            }
        }