private static byte[] ConvertToBytes(string fileFullName)
         {
             using (FileStream fileStream = File.OpenRead(fileFullName))
             {
                 return CopyToArray(fileStream);
             }
         }
 
        private static byte[] CopyToArray(FileStream fileStream)
         {
             using (MemoryStream memoryStream = new MemoryStream())
            {
                 fileStream.CopyTo(memoryStream, (int)fileStream.Length);
                 return memoryStream.ToArray();
             }
         }