index.js

module.exports = function loadImages(images, callback){
  var list = [];
  if (typeof images === 'string') { list = [images]; }
  else { list = [].slice.call(images); }

  var count = 0;
  var loadedImages = {};

  function loaded(){
    count += 1;
    if (count === list.length) { done(null, loadedImages); }
  }

  function done(err, images) {
    if(callback) {
      callback(err, images);
    }
  }

  for (var i=0; i<list.length; i++){
    var img = new Image();

    img.onerror = function(){
      done('images not loaded');
    }

    img.onabort = function(){
      done('images not loaded');
    }

    img.onload = function(){
      loaded();
    }

    img.src = list[i];
    img.name = list[i].slice(list[i].lastIndexOf('/')+1);
    loadedImages[img.name] = img;
  }
};