private void contrastToolStripMenuItem_Click(object sender, EventArgs e) { Bitmap tempImage = source; int contrastValue = Convert.ToInt32(Prompt.ShowDialog("Enter contrast value", "Contrast")); result = new Bitmap(source.Width, source.Height); //initalize the image ImageProcess.EqualisationColored(tempImage, ref source, ref result, contrastValue); outputPic.Image = result; }