Private Sub NumericUpDown1_ValueChanged(sender as Object, e as EventArgs) _ 
     Handles NumericUpDown1.ValueChanged

   MessageBox.Show("You are in the NumericUpDown.ValueChanged event.")

End Sub

imports System
imports System.Drawing
imports System.Windows.Forms

public class ButtonImageList : inherits Form

  dim imgList as ImageList = new ImageList()
    dim lbl as Label 
    dim lnk as LinkLabel
    dim btn as Button
    dim nmbrUpDown as NumericUpDown

  public sub New()
       Size = new Size(300,300)

    dim img as Image
    dim i as integer

    dim arFiles as string() = {"1.ico","2.ico","3.ico","4.ico"}

    for i = 0 to arFiles.Length - 1
      img = Image.FromFile(arFiles(i))
      imgList.Images.Add(img)
    next

    btn = new Button()
    btn.Parent = me
    btn.ImageList = imgList
    btn.ImageIndex = imgList.Images.Count - 1
    btn.Location = new Point(0, 0)
    btn.Size = new Size(200,20)

    '  Create numeric updown to select the image
    nmbrUpDown = new NumericUpDown()
    nmbrUpDown.Parent = me
    nmbrUpDown.Location = new Point(0, 60)
    nmbrUpDown.Value = 0
    nmbrUpDown.Minimum = 0
    nmbrUpDown.Maximum = imgList.Images.Count - 1
    nmbrUpDown.Width = 50
    nmbrUpDown.ReadOnly = true
    AddHandler nmbrUpDown.ValueChanged,AddressOf nmbrUpDown_ValueChanged
    end sub

    public shared sub Main() 
      Application.Run(new ButtonImageList())
    end sub

    private sub nmbrUpDown_ValueChanged(ByVal sender as object,ByVal e as EventArgs)
      dim n as NumericUpDown  = CType(sender, NumericUpDown)
    btn.ImageIndex = CType(n.Value, Integer)
    end sub
end class