public static class Base64Helper    {        /// 
        /// base64字符保存图片到本        /// 
        /// 保存的图片完整路径        /// base64字符串        public static void Base64SaveImage(string filePath, string base64String)        {            try            {                //如果base64是通过http传过来的，要注意其中的%、，、空格等转换，C#规定base64的长度必须是4的倍数，有个别语言是2的倍数，补上==。                base64String = base64String.Trim().Replace("%", "").Replace(",", "").Replace(" ", "+");                if (base64String.Length % 4 != 0)                {                    base64String += "==";                }                byte[] arr2 = Convert.FromBase64String(base64String);                using (MemoryStream ms2 = new MemoryStream(arr2))                {                    System.Drawing.Bitmap bmp2 = new System.Drawing.Bitmap(ms2);                    bmp2.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);                    bmp2.Dispose();                }            }            catch (Exception ex)            {                LogHelper.WriteLog("图片保存异常：" + ex.ToString());            }        }        public static string ImgToBase64String(string Imagefilename)        {            try            {                Bitmap bmp = new Bitmap(Imagefilename);                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();                return Convert.ToBase64String(arr);            }            catch (Exception ex)            {                LogHelper.WriteLog("图片读取异常：" + ex.ToString());                return null;            }        }        public static string ImageToBase64(string path)        {            byte[] bytes = GetPictureData(path);            string base64 = Convert.ToBase64String(bytes);            return base64;        }        public static Bitmap Base64ToImage(string base64)        {            byte[] arr = Convert.FromBase64String(base64);            MemoryStream ms = new MemoryStream(arr);            Bitmap bmp = new Bitmap(ms);            ms.Close();            return bmp;        }        public static byte[] GetPictureData(string imagePath)        {            FileStream fs = new FileStream(imagePath, FileMode.Open);            byte[] byData = new byte[fs.Length];            fs.Read(byData, 0, byData.Length);            fs.Close();            return byData;        }    }