Simple png + jpg optimization script using optipng + jpegtran

optimize_images.rb

#!/usr/bin/ruby

# Instructions

# - Install optipng + libjpeg (http://mxcl.github.com/homebrew/)
# - Put this file in a directory of images
# - Open in TextMate + run it (cmd+r)

# Config

dir = `pwd`.strip
optipng = `which optipng`
jpegtran = `which jpegtran`
png = ".png"
jpg = ".jpg"
suffix = "-opt"
replace = false

# Optimize PNGs

p "Optimizing .pngs in #{dir}"

Dir.glob(dir + "/**/*#{png}", File::FNM_CASEFOLD).each do |f| 

  d = File.dirname(f)
  n = "#{File.basename(f,File.extname(f))}#{suffix}#{png}"
  o = "#{d}/#{n}"

  if replace
    p "- #{f}"
    `#{optipng} #{f}`
  else
    p "- #{f} > #{o}"
    `#{optipng} #{f} -out #{o}`
  end

end

# Optimize JPGs

p "Optimizing .jpgs in #{dir}"

Dir.glob(dir + "/**/*#{jpg}", File::FNM_CASEFOLD).each do |f| 
  d = File.dirname(f)
  n = "#{File.basename(f,File.extname(f))}#{suffix}#{jpg}"
  o = "#{d}/#{n}"

  if replace
    p "- #{f}"
    `#{jpegtran} -optimize #{f}`
  else
    p "- #{f} > #{o}"
    `#{jpegtran} -optimize -outfile #{o} #{f}`
  end
  
end