import (
	"image/color"
	"image/jpeg"
	"net/http"
	"github.com/joshdk/preview"
	"github.com/joshdk/quantize"
)

// Fetch the source image
resp, err := http.Get("https://blog.golang.org/gopher/plush.jpg")
if err != nil {
	panic(err.Error())
}

// Decode jpeg contents
img, err := jpeg.Decode(resp.Body)
if err != nil {
	panic(err.Error())
}

// Reduce image into a palette of 8 colors
colors := quantize.Image(img, 3)

palette := make([]color.Color, len(colors))
for index, clr := range colors {
	palette[index] = clr
}

// Display our new palette
preview.Show(palette)