Reduce picture quality and save it using ASP.Net C#

 I am uploading images in c# windows application. I am uploading the images folder wise. In one folder there are 200 to 3000 images. My one images size is about 3.10 MB to 6.2 MB. Its dimensions are 3008 x 1960, 1960 , 4000 x 2600. 6000 x 4000 . while uploading i am reducing the size of image to 400 x 266 or 266 x 400 depending on the height and width of image. but still my image size is about 227 KB. Now i want to reduce the image resolution to decrease the image size. How i will do it. Please suggest me. My code is given below:

 private void btnUpload_Click(object sender, EventArgs e)
        {
            getDestinationPath();
            string ik = DestinationPath;
            string ik2 = DestinationPath2;          
            string lastFolderName = Path.GetFileName(ik);
            LoginDTO objInsert = new LoginDTO();
            objInsert.CId = Convert.ToInt32(cmbUCat.SelectedValue.ToString());

            if (cmbUScat1.SelectedIndex != -1)
            {
                objInsert.SId = Convert.ToInt32(cmbUScat1.SelectedValue.ToString());
            }
            else
            {
                objInsert.SId = 0;
            }
            if (cmbUScat2.SelectedIndex != -1)
            {
                objInsert.S2Id = Convert.ToInt32(cmbUScat2.SelectedValue.ToString());
            }
            else
            {
                objInsert.S2Id =0;
            }
            if (cmbUScat3.SelectedIndex != -1)
            {
                objInsert.S3Id = Convert.ToInt32(cmbUScat3.SelectedValue.ToString());
            }
            else
            {
                objInsert.S3Id = 0;
            }
            if ((folderBrowserDialog1.SelectedPath).ToString() != "" && (textSource.Text !=""))
            {
                objInsert.FolderPath = DestinationPathWeb;             
                objInsert.FolderName = lastFolderName;
                objInsert.Keywords = txtKeywords.Text;
                string dt = dtpPhotoDate.Value.ToShortDateString();              
                objInsert.PhotoDate = Convert.ToDateTime(dt);
                objInsert.Notes = txtNotes.Text;
                LoginBAL objInsertPhoto = new LoginBAL();
                string ch = objInsertPhoto.InsertPhotoDetails(objInsert);
                int count = Int32.Parse(ch);
                if (count > 0)
                {
                    if (!Directory.Exists(DestinationPath.Trim()))
                    {
                        Directory.CreateDirectory(DestinationPath.Trim());
                    }
                    if (!Directory.Exists(DestinationPath2.Trim()))
                    {
                        Directory.CreateDirectory(DestinationPath2.Trim());
                    }
                    progressBar1.Maximum = Directory.GetFiles(textSource.Text.Trim()).Length;
                    progressBar1.Minimum = 0;
                    progressBar1.Visible = true;
                    foreach (string file in Directory.GetFiles(textSource.Text.Trim()))
                    {
                        string dest = Path.Combine(DestinationPath.Trim(), Path.GetFileName(file));                        
                        File.Copy(file, dest, true);
                        
                        string s = Path.GetFileName(file);
                        if (s != "Thumbs.db")
                        {
                            img = ResizeImage(dest, 400, 400, false);
                            string dest2 = Path.Combine(DestinationPath2.Trim(), Path.GetFileName(file));
                            img.Save(DestinationPath2 + "/" + s);
                            // File.Copy(DestinationPath2 + "/" + img, DestinationPath2, true);

                           SqlCommand cmd = new SqlCommand("insert into FolderImages(FolderName,image) values('" + lastFolderName + "','" + s + "')", con);
                            con.Open();
                            cmd.ExecuteNonQuery();
                        }
                         con.Close();
                         progressBar1.Value = progressBar1.Value + 1;
                    }
                    progressBar1.Visible = false;
                    progressBar1.Value = 0;
                    txtKeywords.Text = "";
                    txtNotes.Text = "";
                    dtpPhotoDate.Text = "";
                    textSource.Text = "";
                    BindUploadFolder();
                    MessageBox.Show("Folder's Images Uploaded successfully.");
                }
                else
                {
                    progressBar1.Visible = false;
                    progressBar1.Value = 0;
                    MessageBox.Show("This Folder "+lastFolderName+" already exists.");
                }
            }
            else
            {
                MessageBox.Show("select Folder of Images.");
            }
        }
        public static Image ResizeImage(string file, int width, int height, bool onlyResizeIfWider)
        {
           
                using (Image image = Image.FromFile(file))
                {
                    // Prevent using images internal thumbnail
                    image.RotateFlip(RotateFlipType.Rotate180FlipNone);
                    image.RotateFlip(RotateFlipType.Rotate180FlipNone);

                    if (onlyResizeIfWider == true)
                    {
                        if (image.Width <= width)
                        {
                            width = image.Width;
                        }
                    }
                    int newHeight = image.Height * width / image.Width;
                    if (newHeight > height)
                    {
                        // Resize with height instead
                        width = image.Width * height / image.Height;
                        newHeight = height;
                    }
                    Image NewImage = image.GetThumbnailImage(width,newHeight,null,IntPtr.Zero);
                    return NewImage;
                }
            
        }