http://labs.lieldulev.com/imagesQueue/ added a list called errorImages array, and use the onerror callback to add those images to the errorImages array. Both onerror and onload check the length of the images array against the queue + errorImages and calls

imagesQueue.js

/*
	imagesQueue.js FULL SOURCE
	A simple, cross-browser, *parallel* images loader object.
	Check http://labs.lieldulev.com/imagesQueue/ for more details.
*/
	imagesQ={
			onComplete: function(){} // Fires when all finished loading
			,onLoaded: function(){} // Fires when an image finishes loading
			,onErrored: function(){} // Fires when an image fails to load
			,current: null // Last loaded image (Image Object)
			,qLength : 0 // the queue length before process_queue
			,errorImages: [] // Images that could not be loaded (array of Image Object)
			,images: [] // Loaded images (array of Image Object)
			,inProcess : false // a flag to indicate if in process_queue
			,queue:[] // Waiting to be processed (array of strings (urls for Image SRC))
			,queue_images: function(){ // gets multiple arguments each can be either an image src or an array of image src (you can mix).
				var arg=arguments;
				for (var i=0;i<arg.length;i++){
					if (arg[i].constructor === Array){
						this.queue= this.queue.concat(arg[i]); // add to queue, do not empty it!
					}else if(typeof arg[i]==='string'){
						this.queue.push(arg[i]);
					}
				}
			}
			,process_queue: function() { // start loading images from the queue
				this.inProcess = true;
				this.qLength += this.queue.length;
				while(this.queue.length >0){
					this.load_image(this.queue.shift()); //pull the next image off the top and load it
				}
				this.inProcess = false;
			}
			,load_image: function(imageSrc){ // load a single by a url and continue to process the queue
				var th = this;
				var im = new Image;
				im .onerror = function(){
					th.current = im ; // set the current
					th.errorImages.push(im ); // add the image to the stack
					(th.onErrored)(); //fire the onerrored
					if(th.queue.length > 0 && !th.inProcess){
						th.process_queue(); // make sure other items are loaded!
					}
					if(th.qLength == th.images.length + th.errorImages.length){ // all images loaded?
						(th.onComplete)(); // call callback
					}
				}
				im .onload = function(){ // After user agent has the image
					th.current = im ; // set the current
					th.images.push(im ); // add the image to the stack
					(th.onLoaded)(); //fire the onloaded
					if(th.queue.length > 0 && !th.inProcess){
						th.process_queue(); // make sure other items are loaded!
					}
					if(th.qLength == th.images.length + th.errorImages.length){ // all images loaded?
						(th.onComplete)(); // call callback
					}//else{// if queue is not empty 
					 //	
					// }
				}
				im .src = imageSrc; // Tell the User Agent to GET the image
			}
		}