Quick and dirty image resizer

batch_resize.rb

require "rmagick"
require "fileutils"

[
  { :path => 'medium', :max_width => 125, :max_height => 450},
  { :path => 'normal', :max_width => 200, :max_height => 200},
  { :path => 'micro', :max_width => 65, :max_height => 65}
].each do |opts|
  max_height = opts[:max_height]
  max_width = opts[:max_width]

  type = opts[:path]
  image_base = File.expand_path(type, File.dirname(__FILE__))
  new_images_base = File.expand_path(type, File.join(File.dirname(__FILE__), 'resized'))

  FileUtils.mkdir_p(new_images_base)

  Dir[image_base + '/*.gif'].each do |image_file|
    image = ::Magick::Image.read(image_file).first
    if image.rows > max_height
      puts "will resize"
      dst = Magick::Image.new(max_width, max_height) {
        self.background_color = 'white'
      }
      resized_image = image.resize_to_fit!(max_width, max_height)
      result = dst.composite(resized_image, Magick::CenterGravity, Magick::OverCompositeOp)
      result.write(File.join(new_images_base, File.basename(image_file)))
    end
  end
end