retina = window.devicePixelRatio > 1
images = document.querySelectorAll('img')

if retina
  search_file_format = (file) ->
    file_match = file.match(/(.+?)(\.\b\w{1,4}$)/)
    if file_match
      file_match[1] + "@2X" + file_match[2]

  [].forEach.call images, (image) ->
    image.src = search_file_format(image.src)