function Thumbnail (path, square) {
  	this.square = square;
  	this.path = path;
  	this.url = Thumbnail.getUrl(path, square);
  	this.image = null;
  	this.loadingDeferred = new $.Deferred();
  }
  
  Thumbnail.map = {};
  Thumbnail.squareMap = {};
  
  Thumbnail.get = function (path, square) {
  	var map = (square) ? Thumbnail.squareMap : Thumbnail.map;
  	if (!map[path]) {
  		map[path] = new Thumbnail(path, square);
  	}
  	return map[path];
  };
  
  Thumbnail.getUrl = function (path, square) {
  	if (square) {
  		return OC.filePath('gallery', 'ajax', 'thumbnail.php') + '?file=' + encodeURIComponent(path) + '&square=1';
  	} else {
  		return OC.filePath('gallery', 'ajax', 'thumbnail.php') + '?file=' + encodeURIComponent(path);
  	}
  };
  
  Thumbnail.prototype.load = function () {
  	var that = this;
  	if (!this.image) {
  		this.image = new Image();
  		this.image.onload = function () {
  			Thumbnail.loadingCount--;
  			that.loadingDeferred.resolve(that.image);
  			Thumbnail.processQueue();
  		};
  		Thumbnail.loadingCount++;
  		this.image.src = this.url;
  	}
  	return this.loadingDeferred;
  };
  
  Thumbnail.queue = [];
  Thumbnail.loadingCount = 0;
  Thumbnail.concurrent = 3;
  Thumbnail.paused = false;
  
  Thumbnail.processQueue = function () {
  	if (!Thumbnail.paused && Thumbnail.queue.length && Thumbnail.loadingCount < Thumbnail.concurrent) {
  		var next = Thumbnail.queue.shift();
  		next.load();
  		Thumbnail.processQueue();
  	}
  };
  
  Thumbnail.prototype.queue = function () {
  	if (!this.image) {
  		Thumbnail.queue.push(this);
  	}
  	Thumbnail.processQueue();
  	return this.loadingDeferred;
  };