base64编码的字符串与图片相互转换

        #region 图片转为base64编码的字符串---ImgToBase64String
        /// <summary>
        /// 图片转为base64编码的字符串
        /// </summary>
        /// <param name="Imagefilename">图片地址</param>
        /// <returns></returns>
        public static List<publicAnnex> ImgToBase64String(string Imagefilename)
        {
            try
            {
                var AList = new List<publicAnnex>();
                var Listarr = Imagefilename.Split(',');
                foreach (var item in Listarr)
                {
                    string uppath = System.Web.HttpContext.Current.Server.MapPath(item);
                    Bitmap bmp = new Bitmap(uppath);
                    MemoryStream ms = new MemoryStream();
                    bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] arr = new byte[ms.Length];
                    ms.Position = 0;
                    ms.Read(arr, 0, (int)ms.Length);
                    ms.Close();
                    var A = new publicAnnex();
                    A.Content = Convert.ToBase64String(arr);
                    AList.Add(A);
                }
                return AList;
            }
            catch (Exception ex)
            {
                return null;
            }
        }
        #endregion

        #region base64编码的字符串转为图片---Base64StringToImage
        /// <summary>
        /// base64编码的字符串转为图片
        /// </summary>
        /// <param name="strbase64">字符串</param>
        /// <returns></returns>
        public static string Base64StringToImage(List<string> strbase64)
        {
            try
            {
                var AnnexAddress = "";
                foreach (var item in strbase64)
                {
                    string time = DateTime.Now.ToString("yyyyMMddHHmmssffff");
                    byte[] arr = Convert.FromBase64String(item);
                    MemoryStream ms = new MemoryStream(arr);
                    Bitmap bmp = new Bitmap(ms);
                    string uppath = System.Web.HttpContext.Current.Server.MapPath("~/UploadFiles/Image/") + "YMD_" + time + ".jpg";
                    bmp.Save(uppath);
                    ms.Close();
                    AnnexAddress += "/UploadFiles/Image/YMD_" + time + ".jpg,";
                }
                AnnexAddress.Substring(0, AnnexAddress.Length - 1);
                return AnnexAddress;
            }
            catch (Exception ex)
            {
                return null;
            }
        }
        #endregion