main.rb

#!/usr/bin/ruby

require 'shellwords'
require 'fileutils'

urls = %w(

)
urls.size.times do |i|
    FileUtils.mkdir_p(i.to_s)
end

loop do
    now = Time.now
    urls.each_with_index do |url, i|
        filename = i.to_s + '/' + now.strftime('%F_%T.jpg')
        cmd = Shellwords.join(%W|wget -nv -O #{filename} #{url}|)
        spawn(cmd)
    end
    sleep 1
end