如何从数据库下载图片？

Question

如何使用vb.net从数据库下载图片。

当我添加插入到数据库中的productimage时。

 For Each file In radasync.UploadedFiles
            Dim ori_path = "../../productimage/"
            Dim path = Server.MapPath(ori_path)
            If System.IO.Directory.Exists(path) Then
                file.SaveAs(path & msGetGID & file.GetName)
            Else
                System.IO.Directory.CreateDirectory(path)
                file.SaveAs(path & msGetGID & file.GetName)
            End If
            filepath = ori_path & msGetGID & file.GetName
        Next
msSQL = " update product" & _
            " set productimage= '" & filepath & "' " & _
            " where productname ='" & GID & "' "

如何下​​载这些图片.....，

<asp:ImageButton ID="download" runat="server" ImageUrl="../../images/downloadfileformat.gif" />

如何编写vb代码....，