Thư Viện WinForm

        //ảnh -> byte[]
        public byte[] imageToByteArray(System.Drawing.Image imageIn)
        {
            MemoryStream ms = new MemoryStream();
            imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            return ms.ToArray();
        }
        //byte[] -> ảnh
        public Image byteArrayToImage(byte[] byteArrayIn)
        {
            MemoryStream ms = new MemoryStream(byteArrayIn);
            Image returnImage = Image.FromStream(ms);
            return returnImage;
        }

        private void btChuyenMa_Click(object sender, EventArgs e)
        {
            DB.tbImage img = new DB.tbImage();
            img.Data = imageToByteArray(ptbAnh.Image);
            
            db.tbImages.InsertOnSubmit(img);
            db.SubmitChanges();
        }

        private void btDichMa_Click(object sender, EventArgs e)
        {
            var data = (from t in db.tbImages
                        where t.ID == 0
                        select t.Data.ToArray()
                       ).SingleOrDefault();
            b = data;
            ptbLayDL.Image = byteArrayToImage(b);
        }