Pixelize works by splitting up the image you want rendered (or duplicated) into a grid of small rectangular areas. Each area is analyzed, and replaced with an image chosen from a large database of images. Pixelize tries to pick images that best match each area.
Pixelize works best when it can choose images from a very large database of images. With about 1000 images, Pixelize can do a reasonable job.
Pixelize is written in C and uses the GIMP Toolkit (GTK) and the Imlib library on top of X11. Pixelize was developed under Linux but has also been tested under SunOS and Solaris. It should work with almost any UNIX, though.