Inspired by The pxl effect with javascript and canvas (and maths), this script creates a similar "pxl"-effect for any input image with a couple of lines of Ruby.
This script requires rmagick for reading the image and haml for writing svg.
$ gem install rmagick
$ gem install haml
Or, simply use the Gemfile in the root directory with bundler.
$ bundle install
$ ./triangle-pixels.rb /path/to/image.jpg 20 50 > /path/to/result.svg
Will load the file /path/to/image.jpg to produce 20 columns of squares, holding two triangles, with a size of 50x50px each (defaults to 20px). The number of rows is calculated according to the geometry of the image. An optional parameter --keep will keep possibly not completely filled edges. The result is written to /path/to/result.svg. You could use software like Inkscape to view, edit, or convert the image.
$ inkscape -f /path/to/result.svg -e /path/to/result.png -C -d 90
Will convert the result to a PNG-image with a dpi of 90.