Share 'Limit Color Count'

Dear Forum,   Been struggling with ways to limit number of colors (RGB) from Image Sampler.   Possible ways I've tried are:   1.  Rounding individual R,G,B values (0 to 1) to specific increments.  The problem with this is that when I bring the RGB values back together with Color RGB(f), the combinations create more colors than intended.     2.  Using the the RGB values as XYZ values, and using cl…