xmldocument as return type for webservices

Question

Hi,

I am sending a xmldocument which consists of a xml file through web
services.

Here, I am retrieving records from database and converting those
records to a xml file format and loading that xml file to xml document
and giving that xmldocument as a return type in my web services.

In this xml file, I am having an image field. So I am converting
that image field to byte[] and in turn converting to base64string i.e

Convert.ToBase64String(Encoding.UTF32.GetBytes(imagefield.Tostring())

I am using asp.net 3.5 with C#.

At client side, I am able to retrieve the xmldocument as xmlnode.

but my problem is,how can I retrieve the individual field data which is
in xmldocument and How can I get the image which is same as in server.

I tried by loading this xmldocument to a dataset and binding to gridview
but I am unable to get the image field even though I used memory stream.

I searched in google but I couldn't get correct solution.

Please help me..