大家帮我看看这个红绿灯交通模拟程序，里面的时间怎么设置才能正确呢？

我想模仿现实生活中的十字路口的红绿灯程序，但是时间我把握不好，希望能得到高人的指点！我用的是Visual Studio 2005!


Public Class Form1

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick '每2秒钟显示绿灯
        PictureBox1.Visible = False '红灯不亮
        PictureBox3.Visible = False '红灯不亮
        PictureBox2.Visible = True '绿灯亮
        PictureBox4.Visible = True '绿灯亮
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Enabled = False
        Timer1.Interval = 2000
        Timer2.Interval = 7000
        Timer2.Enabled = False
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Timer1.Enabled = True
        Timer2.Enabled = True
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Timer1.Enabled = False
        Timer2.Enabled = False
        PictureBox1.Visible = True
        PictureBox2.Visible = True
        PictureBox3.Visible = True
        PictureBox4.Visible = True
    End Sub

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick '每7秒钟显示红灯
        PictureBox1.Visible = True
        PictureBox3.Visible = True
        PictureBox2.Visible = False
        PictureBox4.Visible = False

    End Sub
End Class

我还想问问，这个论坛怎么都不能上传附件了呢?图片也不能上传啊？