application.html

<a href="#" class="show-photos">Show All Photos</a>
<ul id="tourprices">
  <li class="tour" data-loc="london,uk">
    London, UK
    <ul class="photos">
      <li><img src="/assets/photos/london.jpg"></li>
      <li><img src="/assets/photos/london.jpg"></li>
      <li><img src="/assets/photos/london.jpg"></li>
    </ul>
    <a href="#" class="see-photos">See Photos</a>
    <a href="#" class="hide-tour">Hide Tour</a>
  </li>

  <li class="tour" data-loc="paris,france">
    Paris, France
    <ul class="photos">
      <li><img src="/assets/photos/paris1.jpg"></li>
      <li><img src="/assets/photos/paris1.jpg"></li>
      <li><img src="/assets/photos/paris1.jpg"></li>
    </ul>
    <a href="#" class="see-photos">See Photos</a>
    <a href="#" class="hide-tour">Hide Tour</a>
  </li>

  <li class="tour" data-loc="New York, NY, USA">
    New York, NY, USA
    <ul class="photos">
      <li><img src="/assets/photos/newyork1.jpg"></li>
      <li><img src="/assets/photos/newyork1.jpg"></li>
      <li><img src="/assets/photos/newyork1.jpg"></li>
    </ul>
    <a href="#" class="see-photos">See Photos</a>
    <a href="#" class="hide-tour">Hide Tour</a>
  </li>
</ul>

application.js

$.fn.photofy = function(options) {
  this.each(function() {
    var show = function(e) {
      e.preventDefault();
      settings.tour
              .addClass('is-showing-photofy')
              .find('.photos')
              .find('li:gt('+(settings.count-1)+')')
              .hide();
    }
    var settings = $.extend({
      count: 3,
      tour: $(this)
    }, options);
    settings.tour.on('click.photofy', '.see-photos', show);
    settings.tour.on('show.photofy', show);
  });
}

$(document).ready(function() {
  $('.tour').photofy({ count: 1});
  
  $('.show-photos').on('click', function(e) {
    e.preventDefault();
    $('.tour').trigger('show.photofy');
  });
});

problem

We've added an event handler to the "Show all photos" link above the tours. Within this event handler, you'll need to trigger an event, show.photofy, on all tours. Update the plugin to listen for this event and call the show function when it receives it