Image processing is an important topic in which clustering has some application. It's worth pointing out that there are several very good image-processing libraries in Python. scikit-image is a "sister" project of scikit-learn. It's worth taking a look at if you want to do anything complicated.
We will have some fun in this recipe. The goal is to use cluster to blur an image.
First, we'll make use of SciPy to read the image. The image is translated in a 3-dimensional array; the x and y coordinates describe the height and width, and the third dimension represents the RGB values for each image:
# in your terminal $ wget http://blog.trenthauck.com/assets/headshot.jpg