图片的裁剪，两个图片合成一个图片(这是从网上摘的)

/// <summary>

        /// 图片裁剪，生成新图，保存在同一目录下,名字加_new，格式1.png  新图1_new.png

        /// </summary>

        /// <param name="picPath">要修改图片完整路径</param>

        /// <param name="x">修改起点x坐标</param>

        /// <param name="y">修改起点y坐标</param>

        /// <param name="width">新图宽度</param>

        /// <param name="height">新图高度</param>

        public static void caijianpic(String picPath,int x,int y,int width,int height)

        {

            //图片路径

            String oldPath = picPath;

            //新图片路径

            String newPath = System.IO.Path.GetExtension(oldPath);

            //计算新的文件名，在旧文件名后加_new

            newPath = oldPath.Substring(0, oldPath.Length - newPath.Length) + "_new" + newPath;

            //定义截取矩形

            System.Drawing.Rectangle cropArea = new System.Drawing.Rectangle(x, y, width, height);

            //要截取的区域大小

            //加载图片

            System.Drawing.Image img = System.Drawing.Image.FromStream(new System.IO.MemoryStream(System.IO.File.ReadAllBytes(oldPath)));

            //判断超出的位置否

            if ((img.Width < x + width) || img.Height < y + height)

            {

                MessageBox.Show("裁剪尺寸超出原有尺寸！");

                img.Dispose();

                return;

            }

            //定义Bitmap对象

            System.Drawing.Bitmap bmpImage = new System.Drawing.Bitmap(img);

            //进行裁剪

            System.Drawing.Bitmap bmpCrop = bmpImage.Clone(cropArea, bmpImage.PixelFormat);

            //保存成新文件

            bmpCrop.Save(newPath);

            //释放对象

            img.Dispose(); bmpCrop.Dispose();

        }

        /// <summary>

        /// 调用此函数后使此两种图片合并，类似相册，有个

        /// 背景图，中间贴自己的目标图片

        /// </summary>

        /// <param name="sourceImg">粘贴的源图片</param>

        /// <param name="destImg">粘贴的目标图片</param>

        public static Image CombinImage(string sourceImg, string destImg)

        {

            Image imgBack = System.Drawing.Image.FromFile(sourceImg);     //相框图片 

            Image img = System.Drawing.Image.FromFile(destImg);        //照片图片

            //从指定的System.Drawing.Image创建新的System.Drawing.Graphics       

            Graphics g = Graphics.FromImage(imgBack);

            //g.DrawImage(imgBack, 0, 0, 148, 124);      // g.DrawImage(imgBack, 0, 0, 相框宽, 相框高);

            g.FillRectangle(System.Drawing.Brushes.Black, -50, -50, (int)212, ((int)203));//相片四周刷一层黑色边框，这里没有，需要调尺寸

            //g.DrawImage(img, 照片与相框的左边距, 照片与相框的上边距, 照片宽, 照片高);

            g.DrawImage(img, -50, -50, 212, 203);

            GC.Collect();

            string saveImagePath ="D:/测试文件夹/sss.png";

            //save new image to file system.

            imgBack.Save(saveImagePath, ImageFormat.Png);

            return imgBack;

        }