ieViewer1.Image.LoadImage(“test.png");
pictureBox1.Image = CreateImageWithTransparency(ieViewer1.Image);

    public static Image CreateImageWithTransparency(IEImage image)
    {
      const int bytesPerPixel = 4;
      Image originalImage = image.GetNetImage();
      if ((originalImage.PixelFormat & PixelFormat.Indexed) == PixelFormat.Indexed)
      {
        return originalImage;
      }
      Bitmap bmp = new Bitmap(originalImage);
      PixelFormat pxf = PixelFormat.Format32bppArgb;
      Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
      BitmapData bmpData = bmp.LockBits(rect, ImageLockMode.ReadWrite, pxf);
      IntPtr ptr = bmpData.Scan0;
      int numBytes = bmp.Width * bmp.Height * bytesPerPixel;
      byte[] argbValues = new byte[numBytes];
      System.Runtime.InteropServices.Marshal.Copy(ptr, argbValues, 0, numBytes);
      for (int counter = 0, x = 0, y = 0; counter < argbValues.Length; counter += bytesPerPixel)
      {
        int pos = 0;
        pos++; // B value
        pos++; // G value
        pos++; // R value
        argbValues[counter + pos] = (byte)image.GetAlpha(x, y);
        if (++x == bmp.Width)
        {
          x = 0;
          ++y;
        }
      }
      System.Runtime.InteropServices.Marshal.Copy(argbValues, 0, ptr, numBytes);
      bmp.UnlockBits(bmpData);
      return bmp;
    }