Flicker

how can i elliminate the flicker? Below is my code
HELP!!!!!!!!!!!!!

Dim n As Integer
Private Sub cmdStart_Click()
If cmdStart.Caption = "Display" Then
cmdStart.Caption = "Delete"
tmrShow.Enabled = True
Else
cmdStart.Caption = "Display"
tmrHide.Enabled = True
End If
End Sub

Private Sub Form_Load()
n = 1
End Sub

Private Sub tmrHide_Timer()
imgOvr(n).Visible = False
n = n + 1
If n > 5 Then
tmrHide.Enabled = False
n = 1
End If
End Sub

Private Sub tmrShow_Timer()
imgOvr(n).Visible = True
n = n + 1
If n > 5 Then
tmrShow.Enabled = False
n = 1
End If
End Sub