Clear image on picturebox

Question

How can I clear draw image on picturebox? The following doesn't help me:

pictbox.Image = null;
pictbox.Invalidate();

Please help.

EDIT

private void pictbox_Paint(object sender, PaintEventArgs e) 
{ 
     Graphics g = e.Graphics; 
     vl.Draw(g, ref tran.realListForInsert); 
} 

public void Draw(Graphics g, ref List<double> arr) 
{ 
    g.DrawRectangle(new Pen(Brushes.Red, 3), nodeArr[Convert.ToInt32(templstName)].pict.Location.X, nodeArr[Convert.ToInt32(templstName)].pict.Location.Y, 25, 25); 
    g.DrawRectangle(new Pen(Brushes.Green, 3), nodeArr[Convert.ToInt32(templstArgName)].pict.Location.X, nodeArr[Convert.ToInt32(templstArgName)].pict.Location.Y, 25, 25); 
    nodeArr[Convert.ToInt32(templstName)].text.Text = arr[Convert.ToInt32(templstArgName)].ToString(); 
    arr[Convert.ToInt32(templstName)] = arr[Convert.ToInt32(templstArgName)]; 
} 

Answer 1

As others have said, setting the Image property to null should work.

If it doesn't, it might mean that you used the InitialImage property to display your image. If that's indeed the case, try setting that property to null instead:

pictBox.InitialImage = null;