A simple ruby script generate image previews

resize.rb

#!/usr/bin/env ruby

# A simple ruby rmagick resize script.
#
# Example: ./resize.rb /user/joe/mypics 400 533
#
# Searches /user/joe/mypics recursively for all files ending with 'jpg'; the search is case
# insensitive. The found image will be proprtinaly scaled to a max width of 400 pixels and 
# a max height of 533 pixels. The resized image will be written to a new file with the 
# extension 'preview.jpg'
#
# Thats all!

require 'find'
require 'RMagick'
include Magick

if ARGV.length == 0
  puts "Usage: resize.rb /path/to/directory maxwidth maxheight"
  exit 0
end

Find.find(ARGV[0]) do |f|
  if File.fnmatch('*.jpg', f, File::FNM_CASEFOLD)
    target = f.to_s.gsub(/([jJ][pP][gG])/,"preview.#{$1}")
    if not File.exists?(target)
      puts "Resize #{f}"
      original = Magick::Image.read(f).first
      resized = original.resize_to_fit(ARGV[1].to_i, ARGV[2].to_i)
      puts "Write #{target}"
      resized.write(target)
      GC.start
    else
      puts "Skip #{f}"
    end
  end
end