SlackBuildsOrg/graphics/metapixel

Metapixel is a program for generating photomosaics.  It can generate
classical photomosaics, in which the source image is viewed as a
matrix of equally sized rectangles for each of which a matching image
is substitued, as well as collage-style photomosaics, in which
rectangular parts of the source image at arbitrary positions (i.e. not
aligned to a matrix) are substituted by matching images.