Mysqlbackup and musqlworkbench more difference

MySqlWorkBench
- DataExport
- Export to Dump Project Folder
- Select single Table or all
- Include Create Schema
* Start export

ex: same table tb_foto over 18.000 record contain 
two Field TINYBLOB path and filename
field Blob -> image 103 x 100 pixel

result : from MySqlBackup ---- tb_foto.sql -> 104.576 Kb
         from MySqlWorkBench - tb_foto.sql ->  62.799 Kb

why this considerable difference of space between MySqlBackup and MySqlWorkBench

MySqlBackup mb = new MySqlBackup(cmd);

private void BackupTabella(MySqlBackup mb,string path, string tabella, string tabellaSql)
        {                           
            mb.ExportInfo.AddCreateDatabase = true;        //schema db
            mb.ExportInfo.ExportTableStructure = true;     //table structure
            mb.ExportInfo.ExportRows = true;               //data table                     

            List<string> tbex = new List<string>();

            if (tabella != "")
            {
                tbex.Add(tabella);
            }

            string file = path + tabellaSql;

            int found = file.LastIndexOf("Storico");
            if (found > -1)
            {
                found = file.LastIndexOf(tabellaSql);
                if (found > -1)
                {
                    file = file.Substring(0, found) + "\\" + file.Substring(found);
                }
            }

            mb.ExportInfo.TablesToBeExportedList = tbex;   //elenco tabelle se vuoto = tutte
            mb.ExportInfo.GetTotalRowsMode = GetTotalRowsMethod.Skip;           
            mb.ExportToFile(file);
        }