เกิดปัญหาเรื่องการ save ภาพ ของ file Stream (code C#)

        private void timer1_Tick(object sender, EventArgs e)
        {
            timer1.Enabled = false;
            imgCapture.Image = imgVideo.Image;
            SaveCap.SaveImageCapture(imgCapture.Image);
            Bitmap img = new Bitmap(imgCapture.Image);
            AddFilter(img, "PicEnhance_1.bmp");      // ถ้าใช้แบบนี้จะเกิดปัญหาตรงนี้
            FileStream fs = new FileStream("C:\\Picture_1.bmp", FileMode.Open);
            imgShow1.Image = Image.FromStream(fs);
            fs.Close();
            timer2.Enabled = true;              
        }

        private void timer2_Tick(object sender, EventArgs e)
        {
            timer2.Enabled = false;
            imgCapture.Image = imgVideo.Image;
            Helper2.SaveImageCapture2(imgCapture.Image);
            Bitmap img2 = new Bitmap(imgCapture.Image);
            AddFilter(img2, "PicEnhance_2.bmp");
            FileStream fs = new FileStream("C:\\Picture_2.bmp", FileMode.Open); // แล้วตรงนี้จะฟ้องว่ามีการใช้งานโดยส่วนอื่น
            imgShow2.Image = Image.FromStream(fs);
            fs.Close();
            CompareImages();
            if (Math.Abs(A1 - B1) >= 3)
            {
                SendMailAttTo();   //ส่ง email 
                B1 = A1;
            } 
            timer1.Enabled = true;
        }
       //======================
       private void AddFilter(Bitmap image, string fileName)
        {
            //Filter_GrayScale(image);
            image.Save("C:\\" + fileName);
            image.Dispose();
        }
       //======================
       private void CompareImages()
        {

            FileStream fs;
            fs = new FileStream("C:\\PicEnhance_1.bmp", FileMode.Open);
            Bitmap bmp1 = new Bitmap(fs);
            BitmapFilter.Contrast(bmp1, 30);
            BitmapFilter.EdgeDetectDifference(bmp1, 20);
            fs.Close();
            File.Delete("C:\\PicEnhance_1.bmp");
            bmp1.Save("C:\\PicEnhance_1.bmp");
            fs = new FileStream("C:\\PicEnhance_2.bmp", FileMode.Open);
            Bitmap bmp2 = new Bitmap(fs);
            BitmapFilter.Contrast(bmp1, 30);
            BitmapFilter.EdgeDetectDifference(bmp2, 20);
            fs.Close();
            File.Delete("C:\\PicEnhance_2.bmp");
            bmp1.Save("C:\\PicEnhance_2.bmp");

                Color c1, c2;
                int width, height, diff;
                diff = 0;
                width = bmp1.Width; height = bmp1.Height;
                for (int i = 0; i < width; i++)
                {
                    for (int j = 0; j < height; j++)
                    {
                        c1 = bmp1.GetPixel(i, j);
                        c2 = bmp2.GetPixel(i, j);
                        if (!c1.Equals(c2))
                        {
                            diff++;
                        }
                    }
                }
                progressBar1.Value = ((diff * 100) / 76800);
                label1.Text = ((diff * 100) / 76800) + " %";
                A1 = (int)progressBar1.Value;

          }