C#图片转字符串------>>>>字符串在转回图片两种方法

 C#图片转字符串------>>>>字符串在转回图片两种方法

 1  #region 调用方法
        private void Form1_Load(object sender, EventArgs e)
        {
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Multiselect = true;//该值确定是否可以选择多个文件
            dialog.Title = "请选择文件夹";
            dialog.Filter = "所有文件(*.*)|*.*";
            if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                string file = dialog.FileName;
                var imageString = ImageConvertString(file);
                var iamgePath = StringToImage(imageString);

                var downImageString = DownloadImageConvertString(file);
                var downIamgePath = StringConvertImage(imageString);
            }
        } 
        #endregion
        #region 网络图片转换
        public string DownloadImageConvertString(string imagepath)
        {
            using (System.Net.WebClient wc = new System.Net.WebClient())
            {
                wc.Headers.Add("User-Agent", "Chrome");
                return Convert.ToBase64String(wc.DownloadData(imagepath));
            }
        }
        public static string StringConvertImage(string buffer, string fileName = "bg_print1")
        {
            string path = string.Format("{0}/{1}{2}.png", System.Environment.CurrentDirectory, System.DateTime.Now.ToString("yyyyMMddHHmmss"), fileName);
            byte[] bytes = Convert.FromBase64String(buffer);
            MemoryStream ms = new MemoryStream();
            ms.Write(bytes, 0, bytes.Length);
            Bitmap bmp = new Bitmap(ms);
            if (Directory.Exists(path))
            {
                Directory.Delete(path);
            }
            bmp.Save(path);
            return path;
        } 
        #endregion
        #region 本地图片转换
        /// <summary>
        /// Base64String转本地图片
        /// </summary>
        /// <param name="buffer">Base64String</param>
        /// <param name="fileName">文件名</param>
        /// <returns></returns>
        public static string StringToImage(string buffer, string fileName = "bg_print2")
        {
            string path = string.Format("{0}/{1}{2}.png", System.Environment.CurrentDirectory, System.DateTime.Now.ToString("yyyyMMddHHmmss"), fileName);
            using (MemoryStream ms = new MemoryStream(Convert.FromBase64String(buffer)))
            {
                using (Image image = System.Drawing.Image.FromStream(ms))
                {
                    if (Directory.Exists(path))
                    {
                        Directory.Delete(path);
                    }
                    image.Save(path);
                    return path;
                }
            }
        }
        /// <summary>
        /// 本地图片文件转Base64字符串
        /// </summary>
        /// <param name="imagepath">本地文件路径</param>
        /// <returns>Base64String</returns>
        public string ImageConvertString(string imagepath)
        {
            using (FileStream fs = new FileStream(imagepath, FileMode.Open))
            {
                byte[] byData = new byte[fs.Length];
                fs.Read(byData, 0, byData.Length);
                fs.Close();
                return Convert.ToBase64String(byData);
            }
        } 
        #endregion