Web service help.

Hi there, it is my first time creating a webservice so pardon me for my poor knowledge

I need to retrieve filepaths which is stored in my database by using web service. I tried writing the codes as shown below, but it keeps prompt me saying : not all code paths return a value.

  
    [WebMethod]
    public string getImages(int minutesID) 
    {
        
        SAConnection myConnection = new SAConnection(DB_STR);
        
        string filepath;
        //open the connection 
        myConnection.Open();
        //Create a command object. 
        SACommand myCommand = myConnection.CreateCommand();

        SAParameter prms = new SAParameter();
        prms.SADbType = SADbType.Integer;
        myCommand.Parameters.Add(prms);
        myCommand.Parameters[0].Value = minutesID;
        
        //Specify a query. 
        myCommand.CommandText = "SELECT filePath from attachments WHERE minutesID = ?";

        //Create a DataReader for the command 
        SADataReader reader = myCommand.ExecuteReader();



        while (reader.Read()) 
        {
            filepath = reader.GetString(0);
            filepath = Server.MapPath(filepath);
            
            return filepath;
  
            //imagePath.Add(new String(filepath));
        }

I have another query in mind.

1) Should i return string or an array of string which contains the file path?