This graphic is produced by running DominantColors
(new in Mathematica 9) with different values, using the Lena image as the source:
Each row is a list of the dominant colours in an image, when asking for between 2 and 60. However I'm surprised that the order of the colors keeps changing: why would the order depend on how many you asked for?
Have I done something daft in my code? Or I have failed to grasp something obvious in the online documentation? (Either is likely.)
With[{l = ExampleData[{"TestImage", "Lena"}]},
Graphics[
Table[{colorList = DominantColors[l, d];
{Table[{
colorList[[x]],
Rectangle[{x - 1, 10 - d},{x, 10 - (d + 0.7)}]
},
{x, 1, Length@colorList}]}},
{d, 2, 60}]]
]