hoge.rb

require 'rubygems'
require 'rmagick'

width = 100
height= 100

url = 'https://si0.twimg.com/profile_images/3345985110/ce68eba70a439a797006d8451dbe51a7_bigger.gif'
image = Magick::Image.read(url).first
image.resize!(1, 1)
color = image.get_pixels(0, 0, 1, 1)[0];
red   = color.red   / 256
green = color.green / 256
blue  = color.blue  / 256

cmd = 'blink1-tool --rgb %d,%d,%d' % [red, green, blue]
system cmd