picture-tube is only for PNG images.
npm install -g picture-tube#!/bin/sh
convert $1 /tmp/un.png
if test $# -eq 2 ; then
~/node_modules/picture-tube/bin/tube.js --cols $2 /tmp/un.png
else
~/node_modules/picture-tube/bin/tube.js /tmp/un.png
fi
rm /tmp/un.png