Public Class Form1
    Dim WithEvents Btn As New Button With {.Dock = DockStyle.Bottom, .Height = _
      30, .Text = "ShowImage", .Parent = Me}
    Dim WithEvents p As New Process
    Private Sub Btn_MouseDown(sender As Object, e As MouseEventArgs) Handles _
      Btn.MouseDown
        ShowPhotoViewer("D:\VBGrafik\Vogel.jpg")
    End Sub
 
    Private Sub ShowPhotoViewer(file As String)
        If Not IO.File.Exists(file) Then Return
        Dim pfad As String = IO.Path.Combine( _
          Environment.ExpandEnvironmentVariables("%ProgramFiles%"), "Windows" & _
          "Photo Viewer\PhotoViewer.dll")
        p.StartInfo = New ProcessStartInfo("rundll32.exe")
        p.StartInfo.Arguments = Chr(34) & pfad & Chr(34) & "" & _
          "ImageView_Fullscreen " & file
        p.EnableRaisingEvents = True
        p.Start()
    End Sub
 
    Private Sub PhotoViewer_Exited(sender As Object, e As EventArgs) Handles _
      p.Exited
        MsgBox("PhotoViewer wurde beendet")
    End Sub
End Class