Dim num, time As Integer
Private Sub PictureBox1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PictureBox1.Click
Dim show As Integer
If Timer1.Enabled Then
show = MsgBox("还看照片吗？", MsgBoxStyle.YesNo + MsgBoxStyle.Information + MsgBoxStyle.DefaultButton1, "选择")
If show = MsgBoxResult.Yes Then
Timer1.Stop()
End If
Else
Timer1.Start()
End If
End Sub

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
PictureBox1.Image = ImageList1.Images(num)
num = (num + 1) Mod time
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
num = ImageList1.Images.Count
time = 0
End Sub

出现了这个错误，高手们指点一下，谢谢！

我认为有可能是ImageList控件Images的索引值错了，每个图片的序号是从0开始的，也就是说，你最后一个图片的索引号是ImageList1.Images.Count - 1 的值，当你把ImageList1.Images.Count的值赋给num , 然后在PictureBox1.Image = ImageList1.Images(num)时就错了，括号里应该是（num-1）

Dim num As Integer = 1
Dim i As Integer = 0
Private Sub PictureBox1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PictureBox1.Click
Dim show As Integer
If i Mod 2 = 0 Then
PictureBox1.Image = ImageList1.Images(num - 1)
i = i + 1
Else
show = MsgBox("还看照片吗？", MsgBoxStyle.YesNo + MsgBoxStyle.Information + MsgBoxStyle.DefaultButton1, "选择")
If show = MsgBoxResult.Yes Then
PictureBox1.Image = ImageList1.Images(num - 1)
Else
num = num + 1
If num <= ImageList1.Images.Count Then
PictureBox1.Image = ImageList1.Images(num - 1)
Else
MsgBox("图片已经看完", MsgBoxStyle.Information, "提示")
End If
End If
End If
End Sub