The Rasterbator-NG is an application which creates rasterized versions of images. The rasterized images can be printed and assembled into enormous (or smaller, if you prefer) posters.

Rasterbator-NG is a fork from Rasterbator (http://arje.net/rasterbator), because the original programmer didn't react on mails.

Many thanks for this screenshot to Daniel-S-P, who made it: