import urllib2
png = urllib2.urlopen('http://ipython.rossant.net/squirrel.png')
im = imread(png)
im.shape

from PIL import Image
img = Image.fromarray((im*255).astype('uint8'))

imshow(im)

figure(figsize=(10,6))
cmaps = ['Reds', 'Greens', 'Blues']
for i in xrange(3):
    subplot(1, 3, i + 1)
    imshow(im[:,:,i], cmap=get_cmap(cmaps[i]))

imshow(array(img.rotate(45.)))

from scipy.cluster.vq import *
M = im[:,:,0].ravel()
# centroids contains four color clusters in the image
centroids, _ = kmeans(M, 4)
# we associate each pixel to one of the four colors (qnt is in array of integer indices)
qnt, _ = vq(M, centroids)
# finally we obtain the quantized image through fancy indexing
clustered = centroids[reshape(qnt, (300, 300))]

cmap = matplotlib.colors.ListedColormap([(0,.2,.3), (.85,.1,.13), (.44,.6,.6), (1.,.9,.65)])
imshow(clustered, cmap=cmap)

imsave('squirrelama.png', clustered, cmap=cmap)