private static void Change()
        {
            System.IO.FileStream fs = new System.IO.FileStream(@"F:\C盘搬家\My Documents\Wandoujia\Backup\1.jpg", System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.BinaryReader r = new System.IO.BinaryReader(fs);

            System.IO.FileStream fs2 = new System.IO.FileStream(@"F:\C盘搬家\My Documents\Wandoujia\Backup\Backup.rar", System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.BinaryReader r2 = new System.IO.BinaryReader(fs2);

            byte[] newfile = new byte[fs.Length + fs2.Length];
            //byte[] tempbyte = Encoding.Default.GetBytes("7173");
            //for (int i = 0; i < tempbyte.Length; i++)
            //{
            //    newfile[i] = tempbyte[i];
            //}
            //for (int i = tempbyte.Length; i < fs.Length; i++)
            //{
            //    newfile[i] = r.ReadByte();
            //}
            for (int i = 0; i < fs.Length; i++)
            {
                newfile[i] = r.ReadByte();
            }
            for (long i = fs.Length; i < fs.Length + fs2.Length; i++)
            {
                newfile[i] = r2.ReadByte();
            }
           

            FileStream fsout = new FileStream(@"F:\C盘搬家\My Documents\Wandoujia\Backup\Backup.jpg", System.IO.FileMode.Create, System.IO.FileAccess.Write);
            System.IO.BinaryWriter wr = new BinaryWriter(fsout);

            wr.Write(newfile, 0, newfile.Length);
            fsout.Flush();
            fsout.Close();
        }

将图片加在前面就行了啊~~ 哈哈 ~