Delete unused images in a rails project

gistfile1.rb

images = Dir.glob('public/images/*')

images.each do |image|
  unless File.directory?(image)
    puts "Checking #{image}..."
    if IO.popen("ack-grep -1 -G '(app|public)' --ruby --html --css #{File.basename(image)}").eof?
      IO.popen("svn delete #{image}")
      puts "  Deleted"
    end
  end
end and nil