swap images as the mouse moves around the screen...

bg_mouse.js

        ;(function($){

            $.fn.bgMouse = function(argOptions) {

                var FILENAME = argOptions.folder;

                var FILE_COUNT = argOptions.count;

                return this.each(function(index, theContainer) {

                    var $container = $(theContainer);

                    // Add zeros
                    lpad = function(s, width, char) {
                        return (s.length >= width) ? s : (new Array(width).join(char) + s).slice(-width);
                    }

                    // Prepare array with images
                    var imgFilenames = [];
                    for (var i=0; i<FILE_COUNT; i++) {
                        imgFilenames.push(FILENAME + lpad(i, 4, '0') + '.jpg');
                    }

                    // Method to preload images
                    var preloadImages = function(arr){
                        var newimages=[], loadedimages=0
                        var postaction=function(){}
                        var arr=(typeof arr!="object")? [arr] : arr
                        function imageloadpost(){
                            loadedimages++
                            if (loadedimages==arr.length){
                                postaction(newimages) //call postaction and pass in newimages array as parameter
                            }
                        }
                        for (var i=0; i<arr.length; i++){
                            newimages[i]=new Image()
                            newimages[i].src=arr[i]
                            newimages[i].onload=function(){
                                imageloadpost()
                            }
                            newimages[i].onerror=function(){
                                imageloadpost()
                            }
                        }
                        return { //return blank object with done() method
                            done:function(f){
                                postaction=f || postaction //remember user defined callback functions to be called when images load
                            }
                        }
                    }

                    // Method to set BG
                    var setBackground = function(theImages, theIndex) {
                        $container.css('backgroundImage', 'url(' + theImages[theIndex].src + ')');
                    }

                    // Preloading done
                    preloadImages(imgFilenames).done(function(theImages){

                        // By default, set to first img
                        setBackground(theImages, 0);
                        
                        // Mouse position
                        $(window).mousemove(function(theEvent) {
                            var windowWidth = $(window).width();
                            var mouseX = theEvent.pageX;
                            var imgIndex = Math.min(Math.round(mouseX / windowWidth * FILE_COUNT), FILE_COUNT-1);

                            // Set background image
                            setBackground(theImages, imgIndex);
                        });

                    });

                });

            }

        })( jQuery );

call_bgmouse.js

  $('div.bg-animation').bgMouse({
			folder: "/assets/burger-animation/burger_",
			count: 78
		});
    
/* <div class="bg-animation"></div> */
/* background-image: url(http://therewillbeburgers.com/assets/burger-animation/burger_0055.jpg);
}*/