gistfile1.js

// Set API key
var my_flickr = $.flickr({
  apiKey: '123'
});

// Option 1: Inline callbacks
my_flickr.photos.getRecent({
  size: 's'
  page: 1, 
  beforeSend: function() {
    $('img#waiting').fadeIn();
  }, 
  success: function(thumbnails) {
    $('img#waiting').fadeOut();
    $('#photos').append(thumbnails);
  }
});

// Option 2: External callbacks
my_flickr.photos.getRecent({size: 's', page: 1, beforeSend: before, success: after});

function before() {
  $('img#waiting').fadeIn();
}

function after(thumbnails) {
  $('img#waiting').fadeOut();
  $('#photos').append(thumbnails);
}