how to insert image in gridview

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            TableCell tCell = new TableCell();
            // create image 
            Image img = new Image();
            img.ImageUrl = "subheader.jpg";
            // add the image to the cell
            tCell.Controls.Add(img);
            
            GridView gView = (GridView)sender;
            // set the colspan to occupy the other cells in the row
            int colSpan = gView.Columns.Count;
            tCell.Attributes["ColSpan"] = colSpan.ToString(); 
 
            GridViewRow gRow = new GridViewRow(-1, -1, DataControlRowType.DataRow, DataControlRowState.Normal);
            // add the cells to the gridviewrow
            gRow.Cells.Add(tCell);
 
            Table tbl = (Table)e.Row.Parent;
 
            // set the pagesize initially to the pagecount/2
            // in our case it is 10/2 = 5. So the first image will 
            // displayed after the 5th row.
            if(pgSize == 0)
                pgSize = GridView1.PageCount / 2;
 
            // This step is performed so that we can display the image only after every 
            // 5, 15, 25 ,35 rows and so on ...
            // The logic is not perfect but will give you the idea
            if (Convert.ToDouble(e.Row.DataItemIndex + 1) / Convert.ToDouble(pgSize) == 1.0)
            {
                tbl.Controls.AddAt(gView.Controls[0].Controls.Count, gRow);
                // add 10 to the pgsize so that the image can be displayed
                // at rows 5, 15, 25 and so on..
                pgSize = pgSize + 10;
            }
        }
    }