how to bind the image from the sharepoint list in gridview using vs 2010 as webpart

<asp:GridView ID="gvPictureLibrary" AutoGenerateColumns ="False" 

    runat="server" EnableModelValidation="True">

</asp:GridView>

Code-behind:

protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                SPWeb site = SPContext.Current.Web;

                SPList list = site.Lists["PL"];

                DataTable dt = new DataTable();

                dt.Columns.Add("ImageUrl", typeof(string));

                DataRow dr;

                foreach (SPListItem item in list.Items)

                {

                    dr = dt.Rows.Add ();

                    dr["ImageUrl"] = item["ows_EncodedAbsThumbnailUrl"].ToString();

                }

                ImageField colImage = new ImageField();

                colImage.DataImageUrlField = "ImageUrl";

                colImage.HeaderText = "Image";

                gvPictureLibrary.Columns.Add(colImage);

                gvPictureLibrary.DataSource = dt;

                gvPictureLibrary.DataBind();

            }

        }