Yes, there is one called Tile Creator. It allows you to scan an image you want to reproduce in tile mosaic, and tells you exactly what mosaic tiles to buy. Sort of a tile by number idea. Here are a couple of links. The first software program allows you to create a mosaic comprised of straight rows of square tiles. The second link

is a program that allows you to position the tiles in random positions (opus vermiculatum style).
www.tilecreator.com/www.tilecreatorartistic....