How do I create a gradient map from an image? [solved]

[rich2005]

I think this is what you are looking for, an old procedure. 

Lots of right clicking involved.

1. Open the palettes dock, I detached it here to make it easier to see.

2. Right click, select Import palette. In the dialogue, select image - number of colours - give it a name.

   

3. Right click on your new palette, select Sort Palette In the dialogue choose Saturation.

   

4. Right click in the sorted palette, click Palette to Gradient