New Post: Total Unique Colors of an image?

I need to get the total number of unique colors, currently i use this:

        Dim histogram As Dictionary(Of MagickColor, Integer) = IMG.Histogram
        MsgBox(histogram.Count)

Works great, however i wondered if there is a property in Magick.NET that already has read the number of colors when i load an image into it? I am trying to save up on operations :)

Thanks!