Get the dimensions of an image using ruby's image_size gem

image_dimensions.rb

#!/usr/bin/env ruby

require 'image_size'

pwd = File.dirname(__FILE__)

Dir.glob(pwd+'/*') do |file|
  if (File.extname(file) == '.jpg')
    fh = File.open(file, 'rb')
    size = ImageSize.new(fh.read)
    puts "[#{size.w}x#{size.h}] #{file}"
  end 
end