C# 文字图片生成与背景图片合成

最近有个需求是将生成的邀请码与背景图片合成成为新的图片，查找了一些资料后又整理了一遍，查到了一个群主的帖子，虽然代码略微有点问题，地址是：https://www.cnblogs.com/stulzq/p/6137715.html，下面上修改后的代码，有两个资源图片，是自己做的，第一个是背景图片（500*600），第二个是前景图片（200*200）。

 public ActionResult Index()
        {
            //生成邀请码图片 字符间距 带空格比较简单
            //Image img = CreateImage("1 2 3 4 5 6", true, 12);

            //修改照片分辨率大小
            //img = ResizeImage(img, 200, 100);

            //保存邀请码图片
            //img.Save("D:/3.jpg");

            //开始合并图片
            Image ibpic = Image.FromFile("D:/1.jpg");
            Image inpic = Image.FromFile("D:/2.jpg");
            Bitmap bmp = CombinImage(ibpic, inpic, 0, -100);
            bmp.Save("D:/4.jpg", ImageFormat.Jpeg);

            return View();
        }

　　　　 /// <summary>
        /// 生成文字图片
        /// </summary>
        /// <param name="text"></param>
        /// <param name="isBold"></param>
        /// <param name="fontSize"></param>
        public Image CreateImage(string text, bool isBold, int fontSize)
        {
            int wid = 400;
            int high = 200;
            Font font;
            if (isBold)
            {
                font = new Font("Arial", fontSize, FontStyle.Bold);

            }
            else
            {
                font = new Font("Arial", fontSize, FontStyle.Regular);

            }
            //绘笔颜色
            SolidBrush brush = new SolidBrush(Color.Black);
            StringFormat format = new StringFormat(StringFormatFlags.NoClip);
            format.Alignment = StringAlignment.Center;
            format.LineAlignment = StringAlignment.Center;
            Bitmap image = new Bitmap(wid, high);
            Graphics g = Graphics.FromImage(image);
            g.Clear(Color.White);//透明

            RectangleF rect = new RectangleF(0, 0, wid, high);
            //绘制图片
            g.DrawString(text, font, brush, rect, format);
            //释放对象
            g.Dispose();
            return image;
        }

        /// <summary>  
        /// 合并图片  
        /// </summary>  
        /// <param name="imgBack"></param>  
        /// <param name="img"></param>  
        /// <returns></returns>  
        public static Bitmap CombinImage(Image imgBack, Image img, int xDeviation = 0, int yDeviation = 0)
        {
            Bitmap bmp = new Bitmap(imgBack.Width, imgBack.Height);
            Graphics g = Graphics.FromImage(bmp);
            g.Clear(Color.White);
            g.DrawImage(imgBack, 0, 0, imgBack.Width, imgBack.Height);
            //白色边框
            g.FillRectangle(System.Drawing.Brushes.White, imgBack.Width / 2 - img.Width / 2 + xDeviation - 1, imgBack.Height / 2 - img.Height / 2 + yDeviation - 1, img.Width + 2, img.Height + 2);
            //填充图片
            g.DrawImage(img, imgBack.Width / 2 - img.Width / 2 + xDeviation, imgBack.Height / 2 - img.Height / 2 + yDeviation, img.Width, img.Height);
            GC.Collect();
            return bmp;
        }

        /// <summary>  
        /// Resize图片  
        /// </summary>  
        /// <param name="bmp">原始Bitmap</param>  
        /// <param name="newW">新的宽度</param>  
        /// <param name="newH">新的高度</param>  
        /// <returns>处理以后的图片</returns>  
        public static Image ResizeImage(Image bmp, int newW, int newH)
        {
            try
            {
                Image b = new Bitmap(newW, newH);
                Graphics g = Graphics.FromImage(b);

                // 插值算法的质量    
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height),
                            GraphicsUnit.Pixel);
                g.Dispose();
                return b;
            }
            catch
            {
                return null;
            }
        }