.net 图片合成大图

int pheight = ((imageFiles.Count / num) + 1) * (sheight); //计算大图高度


            List<Rectangle> Rects = new List<Rectangle>();
            List<System.Drawing.Image> imgs = new List<System.Drawing.Image>();
            System.Drawing.Image img;
            System.Drawing.Image sImg;

            try
            {

                if (picPath == "")
                {
                    img = new Bitmap(pwidth, pheight);//画颜色背景
                }
                else
                {
                    img = Bitmap.FromFile(picPath);//画图片背景
                }


                foreach (string item in imageFiles)//加载小图片;
                {
                    sImg = Bitmap.FromFile(item);
                    imgs.Add(sImg);
                }

                Pen pen = new Pen(GetColor(borderbg), borderSize);//加边框



                //先画行，再画列
                for (int i = 0; i < pheight; i += sheight)
                {
                    for (int j = 2; j < pwidth; j += pwidth / num)
                    {
                        Rectangle rect = new Rectangle(j, i, swidth, sheight);
                        Rects.Add(rect);
                    }
                }



                Graphics g = Graphics.FromImage(img);


                if (picPath == "")
                {
                    g.Clear(GetColor(imagebg));
                }



                string subNum = "";//截取图片后四位做编号
                //根据小图的个数画出
                for (int i = 0; i < imgs.Count; i++)
                {
                    subNum = imageFiles[i].Substring(imageFiles[i].LastIndexOf("\\") + 1);
                    if (subNum.IndexOf("-") > 0)
                    {
                        subNum = subNum.Substring(0, subNum.IndexOf("-"));
                    }
                    else
                    {
                        subNum = subNum.Substring(0, subNum.IndexOf("."));
                    }
                    subNum = subNum.Substring(subNum.Length - 4, 4);

                    g.DrawRectangle(pen, Rects[i]);//给每个小图片加上边框
                    g.DrawImage(imgs[i], Rects[i]);
                    g.DrawString(subNum, new Font("Arial", 10, FontStyle.Bold), new SolidBrush(Color.Red), Rects[i]);
                }

                string filePath = savePath + "\\" + ProductSKU + "\\" + ProductSKU + ".jpg";//保存路径

                saveTempPath += "\\" + ProductSKU + ".jpg";//临时工 = =！


                MemoryStream ms = new MemoryStream();//放入内存，方便页面显示
                img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                if (!Directory.Exists(Path.GetDirectoryName(filePath)))
                {
                    Directory.CreateDirectory(Path.GetDirectoryName(filePath));
                }
                
                
                if (File.Exists(filePath))//如果存在就替换
                {
                    img.Save(saveTempPath, System.Drawing.Imaging.ImageFormat.Jpeg);//临时工派上上场了
                    File.Copy(saveTempPath, filePath, true);
                    if (File.Exists(saveTempPath))
                    {
                        File.Delete(saveTempPath);
                    }
                }
                else
                {
                    img.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);//保存
                }


                SplitIMG(filePath, pheight / (sheight), pwidth, sheight, savePath);

                
                ms.Dispose();
                g.Dispose();
                img.Dispose();

                foreach (var i in imgs)
                {
                    i.Dispose();
                }

                Response.ClearContent();
                Response.ContentType = "image/Jpeg";
                Response.BinaryWrite(ms.ToArray());
            }
            catch (Exception ex)
            {
                Response.WriteFile(ex.Message);
            }

获取文件夹下的图片

public List<string> ImageFile(string path)
        {
            List<string> PicFile = new List<string>();
            FileInfo fi;
            if (!Directory.Exists(path))
            {
                throw new FileNotFoundException();
            }

            foreach (var i in Directory.GetFiles(path))
            {
                fi = new FileInfo(i);
                if (fi.Extension.ToLower() == ".jpg" || fi.Extension.ToLower() == ".gif" || fi.Extension.ToLower() == ".bmp")
                {
                    PicFile.Add(i);
                }
            }

            return PicFile;
        }

分成小图

/// <summary>
        /// 分成小图
        /// </summary>
        /// <param name="filePath">图片路径</param>
        /// <param name="splitNum">分成几份</param>
        /// <param name="w"></param>
        /// <param name="h"></param>
        /// <param name="savePath"></param>
        public void SplitIMG(string filePath, int splitNum, int w, int h, string savePath)
        {

            Bitmap bitmap;
            Graphics g;

            try
            {
                System.Drawing.Image img = Bitmap.FromFile(filePath);


                for (int i = 0; i < splitNum; i++)
                {
                    using (bitmap = new Bitmap(w, h))
                    {
                        g = Graphics.FromImage(bitmap);
                        g.DrawImage(img, new Rectangle(0, 0, w, h), new Rectangle(0, h * i, w, h), GraphicsUnit.Pixel);
                        bitmap.Save(savePath + "\\" + ProductSKU + "\\" + ProductSKU + "_" + (i + 1) + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
                    }
                    g.Dispose();
                }

            }
            catch (Exception ex)
            {
                Response.Write(ex.Message);
                return;
            }
            finally
            {
            }
        }