c#任务中的私有变量

我有一个转换JPG文件的代码。我用任务来加快速度。它是更快，但它搅乱了图像和他们的日期。对我来说，这就像变量在不同的线程之间共享，这使得图像中的变量用于循环中的下一个/另一个图像。是否有办法确保循环中的所有变量在当前任务/线程中都是私有的?

下面是我的代码:

int intImageW, intImageH, intImageWtmp;
DateTime creationTime, lastWriteTime, lastAccessTime;
Parallel.ForEach(strarrFileList, strJPGImagePath =>
    {
        Bitmap bmpDest = new Bitmap(1, 1);
        creationTime = File.GetCreationTime(strJPGImagePath);
        lastWriteTime = File.GetLastWriteTime(strJPGImagePath);
        lastAccessTime = File.GetLastAccessTime(strJPGImagePath);
        using (Bitmap bmpOrig = new Bitmap(strJPGImagePath))
        {
            //Bitmap bmpOrig = new Bitmap(strJPGImagePath);
            intImageW = bmpOrig.Width;
            intImageH = bmpOrig.Height;
            if ((intImageW > intImageH) && (intImageW > intLongSide))
            {
                intImageH = (int)((double)intImageH / ((double)intImageW / (double)intLongSide));
                intImageW = intLongSide;
            }
            else if ((intImageH > intImageW) && (intImageH > intLongSide))
            {
                intImageW = (int)((double)intImageW / ((double)intImageH / (double)intLongSide));
                intImageH = intLongSide;
            }
            else if ((intImageH == intImageW) && (intImageW > intLongSide))
            {
                intImageH = intLongSide;
                intImageW = intLongSide;
            }
            else
            {
                // do something
            }
            // FIX THE ORIENTATION
            if (Array.IndexOf(bmpOrig.PropertyIdList, 274) > -1)
            {
                var orientation = (int)bmpOrig.GetPropertyItem(274).Value[0];
                switch (orientation)
                {
                    case 1:
                        // No rotation required.
                        break;
                    case 2:
                        bmpOrig.RotateFlip(RotateFlipType.RotateNoneFlipX);
                        break;
                    case 3:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate180FlipNone);
                        break;
                    case 4:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate180FlipX);
                        break;
                    case 5:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate90FlipX);
                        break;
                    case 6:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate90FlipNone);
                        intImageWtmp = intImageW;
                        intImageW = intImageH;
                        intImageH = intImageWtmp;
                        break;
                    case 7:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate270FlipX);
                        break;
                    case 8:
                        bmpOrig.RotateFlip(RotateFlipType.Rotate270FlipNone);
                        break;
                }
                bmpOrig.RemovePropertyItem(274);
            }
            bmpDest = new Bitmap(bmpOrig, new Size(intImageW, intImageH));
        }
        bmpDest.Save(strJPGImagePath, jgpEncoder, myEncoderParameters);
        bmpDest.Dispose();
        GC.Collect(2, GCCollectionMode.Forced);
        File.SetCreationTime(strJPGImagePath, creationTime);
        File.SetLastWriteTime(strJPGImagePath, lastWriteTime);
        File.SetLastAccessTime(strJPGImagePath, lastAccessTime);
    });

问题来自这些变量: