find_missing_frames.rb

#!/usr/bin/env ruby

require 'fileutils'

FileUtils.cd("/Users/drew/Desktop/ladder") do
  prev_num = -1;
  i = 0;
  Dir['*.png'].each do |filename|
    number = /ladybug_panoramic_(\d{6}).png/.match(filename)[1]
    num_i = number.to_i
    puts "frame #{num_i-1} missing" if num_i != prev_num + 1
    prev_num = num_i
  end
end