/// <summary>
/// Shows the how the border will look like in the pictureBox.
/// </summary>
private void Preview()
{
var image = new Bitmap(pbExample.Size.Width - 1, pbExample.Size.Height - 1);
image = ImageUtil.Border(image, (float)numThick.Value, pbOutlineColor.BackColor);
pbExample.Image = image;
GC.Collect();
}