preview pictures in image tool

I want to change the pic if the user press on the image button 

i  add the pic to local resource :

but the picture doesn't change:(

Protected Sub ImageButton1_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ImageButton1.Click

Dim I As Integer
I = Rnd() * 8
Select Case I
Case 1
Image1.ImageUrl = "http://localhost:2542/WebSite4/resource/App_LocalResources/161189_100000124129941_6428426_n.jpg"
Case 2
Image1.ImageUrl = "http://localhost:2542/WebSite4/resource/App_LocalResources/13338_101998866489928_100000394454162_47573_4287890_a.jpg"
End Select

End Sub