yes, useTableCell1.Style["background-image"] = "url(http://www.csdn.net/images/csdn.gif)";for example:<script language=C# runat=server>
void Page_Load(Object o, EventArgs e)
{
  t.Rows[0].Cells[0].Style["background-image"] = "url(http://www.csdn.net/images/csdn.gif)";
}
</script>
<asp:Table id="t" runat=server>
  <asp:TableRow>
  <asp:TableCell Width="120" Height="60"> 1 </asp:TableCell> <asp:TableCell>2 </asp:TableCell>
<asp:TableCell> 3 </asp:TableCell> <asp:TableCell Width="120" Height="60" Style="background-image:url(http://www.csdn.net/images/csdn.gif)">4 </asp:TableCell>
  </asp:TableRow>
</asp:Table>