อยากจะลบรูปที่อยู่ในFolder ก่อนที่จะอัพเดทอันใหม่เข้ามาคะ

  newid = Request.QueryString("newid")

        If Not Page.IsPostBack() Then
            Dim SelectCommand As String = "SELECT * FROM news WHERE newid = '" & newid & "' "
            Dim da As New SqlDataAdapter(SelectCommand, conn)
            da.Fill(ds, "select")
            dt = ds.Tables("select").Rows(0)
            lbldate.Text = dt("date")
            txtTitle.Text = dt("title")
            txtDetail.Text = dt("detail")
            imgEdit.ImageUrl = "upload/" & dt("fileupload")

        End If

    End Sub
    Protected Sub btnCon_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCon.Click

        Dim UpdateCommand As String
        Dim strfilename As String

        If Trim(FileUpload1.FileName) = "" Then
            strfilename = ""
        Else
            strfilename = FileUpload1.FileName

            If Me.FileUpload1.HasFile Then

                Dim intWidth, intHeight As Integer
                Dim UiFileName, NewFileName As String

                If FileUpload1.HasFile Then
                    UiFileName = Server.MapPath("upload/") & FileUpload1.FileName
                    If File.Exists(UiFileName) Then
                        File.Delete(UiFileName)
                    End If
                    FileUpload1.SaveAs(UiFileName)


                    intWidth = 100 '*** Fix Width ***'
                    intHeight = 0   '*** If = 0 Auto Re-Cal Size ***'
                    intHeight = 100

                    NewFileName = "upload/Thumbnail_" & FileUpload1.FileName

                    Dim objGraphic As System.Drawing.Image = System.Drawing.Image.FromFile(UiFileName)

                    Dim objBitmap As Bitmap
                    '*** Calculate Height ***'
                    If intHeight > 0 Then
                        objBitmap = New Bitmap(objGraphic, intWidth, intHeight)
                    Else
                        If objGraphic.Width > intWidth Then
                            Dim ratio As Double = objGraphic.Height / objGraphic.Width
                            intHeight = ratio * intWidth
                            objBitmap = New Bitmap(objGraphic, intWidth, intHeight)
                        Else
                            objBitmap = New Bitmap(objGraphic)
                        End If
                    End If
                    '*** Save As  ***'

                    objBitmap.Save(Server.MapPath(NewFileName), objGraphic.RawFormat)
                    '*** Close ***'
                    objGraphic.Dispose()
                End If
        End If
            End If

            UpdateCommand = " UPDATE news " & _
            " SET title ='" & txtTitle.Text & "'," & _
            " detail ='" & txtDetail.Text & "'," & _
            " fileupload ='" & strfilename & "'" & _
            " WHERE newid =" & newid & ""

            Dim com As New SqlCommand(UpdateCommand, conn)
            With com
                .Connection = conn
                .CommandType = CommandType.Text
                .CommandText = UpdateCommand
                .ExecuteNonQuery()
            End With
            Response.Redirect("viewAddnews.aspx")
    End Sub