task "images:compress" => :environment do io = ImageOptim.new images = Dir.glob("#{Rails.root}/app/**/*.png") image_sizes = Hash[*images.map{|i| [i,File.size(i)]}.to_a.flatten] io.optimize_images!(images) do |name, optimized| if optimized new_size = File.size(name) puts "#{name} => from: #{image_sizes[name.to_s]} to: #{new_size}" end end end