删除图片时，文件正被一进程使用中。。请高手帮忙看下。在线等

Question

           Stream st = File1.PostedFile.InputStream; 
                    System.Drawing.Bitmap map = new Bitmap(st);
                        //调整图片的长短比 
                        double dl = 1;
                        //设置最大长度
                        double maxlength = 300;
                        if (map.Width >= map.Height)
                        {
                            dl = (double)(maxlength / (double)map.Width);//求比例                        }
                        else
                        {
                            dl = (double)(maxlength / (double)map.Height);
                        }
                        //构建新的图片 
                        System.Drawing.Bitmap newmap = new Bitmap(map, (int)(map.Width * dl), (int)(map.Height * dl));
                        //Response.Clear();
                        //图片保存     webFilePath为图片保存路径
                        newmap.Save(webFilePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                        //释放内存 
                        map.Dispose();
                        newmap.Dispose();
                        //=========================
                        Session["path"] = webFilePath;                        System.Drawing.Image uploadImage = System.Drawing.Image.FromFile(webFilePath);
                        UpImg.PhotoMode modes = (uploadImage.Width > uploadImage.Height ? UpImg.PhotoMode.W : UpImg.PhotoMode.H);//判断图片宽与高的长度，选择合适的压缩方式
                        UpImg.MakeThumbnail(webFilePath, webFilePath_s, 130, 130, modes);     // 生成缩略图方法        /**/
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式</param>    
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, PhotoMode mode)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
            int towidth = width;
            int toheight = height;            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;            switch (mode)
            {
                case PhotoMode.HW:
                    break;
                case PhotoMode.W:
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case PhotoMode.H:
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case PhotoMode.Cut:
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }
            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;            //清空画布并以透明背景色填充
            g.Clear(System.Drawing.Color.Transparent);            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
                new System.Drawing.Rectangle(x, y, ow, oh),
                System.Drawing.GraphicsUnit.Pixel);            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }

Answer 1

上传后，我再删除就出现文件正在使用中的问题。 我在本机可以删除，没有问题，就是在局域网其它机子访问的时候，出现此问题。 
但是如果，我在上传的代码后面加个File.Delete(路径），把其它代码都屏掉，这个文件是可以删掉的，，其它机子也可以， 是不是生成缩略图里出了问题啊？或者什么资源什么的没释放，我看来看去都已经释放了呀。。 很疑惑。。大家来帮忙看下呀 

Answer 2

System.Drawing.Image uploadImage = System.Drawing.Image.FromFile(webFilePath);
UpImg.PhotoMode modes = (uploadImage.Width > uploadImage.Height ? UpImg.PhotoMode.W : UpImg.PhotoMode.H);//判断图片宽与高的长度，选择合适的压缩方式//拿到图片大小后释放图片资源
uploadImage.Dispose();
uploadImage = null;UpImg.MakeThumbnail(webFilePath, webFilePath_s, 130, 130, modes);     // 生成缩略图方法

Answer 3

System.Drawing.Image uploadImage = System.Drawing.Image.FromFile(webFilePath);这个未释放