Convert multi-format images to JPG (using ImageMagick on ruby)

image2jpg.rb

#!/usr/bin/env ruby

# Convert non-destructive format(PNG/BMP/TIFF) images to JPEG
# (for Windows, runs on git bash only)
# 
# Requires ImageMagick: set correct ImageMagick path as below
# (e.g. convert.exe collides with Windows system command)
IM_PATH = 'C:/usr/ImageMagick'
IM_CONVERT = "#{IM_PATH}/convert"

require 'find'
require 'pathname'
require 'fileutils'

# puts + flush (required to display progress: git bash has big buffer!)
def puts(s) # overrides Kernel.puts
  STDOUT.puts s
  STDOUT.flush
end

exit_code = 0

Find.find(ARGV[0] ? ARGV[0].encode(Encoding::UTF_8) : '.') do |f|
  src = Pathname.new f
  next unless src.file?
  ext = src.extname
  next unless ['.PNG','.BMP','.TIF','.TIFF'].index ext.upcase
  dst = src.dirname + "#{src.basename ext}.jpg"
  if dst.exist?
    puts "WARNING(#{ext} => .jpg): \"#{dst}\" already exists (skipped)"
    exit_code = -2
  else
    if system "#{IM_CONVERT} \"#{src}\" \"#{dst}\""
      puts "\"#{src}\" => .jpg"
      FileUtils.rm src
    else
      puts "ERROR(#{ext} => .jpg): cannot generate \"#{dst}\""
      exit_code = -1
    end
  end
end
exit exit_code