cleanup.rb

#!/usr/bin/env ruby
require 'ftools'

EXTS = %w{ jpg gif jpeg png }
DEST = '/Users/capotej/Pictures'

def cleanup?(p)
  return true unless EXTS.select { |f| p.to_s.include?(f) or p.to_s.include?(f.upcase) }.empty?
end


Dir["/Users/capotej/Desktop/*"].each do |p|
  if cleanup?(p)
    unless File.exists?(DEST + '/' + File.basename(p))
      File.move(p, DEST)
    else
      new_name = p + ".dup#{rand(123123)}"
      File.rename(p, new_name)
      File.move(new_name, DEST)
    end
  end
end