1  
   2          public static Image SetOpacity(Image original, float opacity)
   3          {
   4              Bitmap temp = new Bitmap(original.Width, original.Height);
   5              Graphics g = Graphics.FromImage(temp);
   6              ColorMatrix cm = new ColorMatrix();
   7              cm.Matrix33 = opacity;
   8  
   9              ImageAttributes ia = new ImageAttributes();
  10              ia.SetColorMatrix(cm, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
  11              g.DrawImage(original, new Rectangle(0, 0, temp.Width, temp.Height), 0, 0, original.Width, original.Height, GraphicsUnit.Pixel, ia);
  12              g.Dispose();
  13  
  14              return temp;
  15          }