private Image CreateDropDownImage(Color color)
{
// Create image that has an alpha channel
Image image = new Bitmap(9, 9, PixelFormat.Format32bppArgb);
// Use a graphics instance for drawing the image
using (Graphics g = Graphics.FromImage(image))
{
// Draw a solid arrow
using (SolidBrush fill = new SolidBrush(color))
g.FillPolygon(fill, new Point[] { new Point(2, 3), new Point(4, 6), new Point(7, 3)});
// Draw semi-transparent outline around the arrow
using(Pen outline = new Pen(Color.FromArgb(128, color)))
g.DrawLines(outline, new Point[]{ new Point(1, 3), new Point(4,6), new Point(7, 3)});
}
return image;
}