Refactor or not to refactor - that is the question: Whether 'tis nobler in the mind to suffer. The slings and arrows of outrageous fortune. Or to take arms against a sea of troubles. And by opposing end them.

version_01.rb

  def prev_photo_url(album, photo, **options)
    prev_photo_id = album.prev_photo_id(photo)
    album_photo_url album, prev_photo_id, options if prev_photo_id
  end
  def prev_photo_path (album, photo, **options)
    prev_photo_url(album, photo, {only_path: true}.merge!(options))
  end

  def next_photo_url(album, photo, **options)
    next_photo_id = album.next_photo_id(photo)
    album_photo_url album, next_photo_id, options if next_photo_id
  end
  def next_photo_path (album, photo, **options)
    next_photo_url(album, photo, {only_path: true}.merge!(options))
  end

version_02.rb

  [:path, :url].each do |variant|
    define_method "prev_photo_#{variant}" do |album, photo, **options|
      prev_photo_id = album.prev_photo_id(photo)
      send("album_photo_#{variant}", album, prev_photo_id, options) if prev_photo_id
    end

    define_method "next_photo_#{variant}" do |album, photo, **options|
      next_photo_id = album.next_photo_id(photo)
      send("album_photo_#{variant}", album, next_photo_id, options) if next_photo_id
    end
  end