The Control.Enabled property (=false) should do it...  or just create a copy
of your image replacing all white with the light grey and every other color
with dark grey.

Cheers
Daniel
--
http://www.danielmoth.com/Blog/

So it will get like disabled, convert a certain Image as grayscale by
computing Y value (is the grayscale component in YIQ) by this formula:

Y = 0.299 * R + 0.587 * G + 0.114 * B

and then use Y value as R, G, B parameters for a color. See the code
snippet bellow, "dst" variable will contain grayscale image from
"source" bitmap:

Bitmap dst = new Bitmap(source.Width, source.Height);

for(int y=0; y < dst.Height;y++)
{
    for(int x=0; x < dst.Width; x++)
    {
        Color c = source.GetPixel(x, y);
        // alternatively Y = (77 * c.R + 150 * c.G + 29 * c.B) >> 8
        int Y = (int)(c.R * 0.299 + c.G * 0.587 + c.B * 0.114);
        dst.SetPixel(x, y, Color.FromArgb(Y, Y, Y));
    }
}

Hope this help,
Sergey Bogdanov
http://www.sergeybogdanov.com