jQuery(document).ready(function($){
        // Fade in images so there isn't a color "pop" document load and then on window load
        $(".grayscale").fadeIn(500);
        // clone image
        $('.grayscale').each(function(i){
            var el = $(this);
            el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
                var el = $(this);
                el.parent().css({"width":this.width,"height":this.height});
                el.dequeue();
            });
            grayscale(this.src, i);
        });
        // Fade image
        $('.grayscale').mouseover(function(){
            $(this).parent().find('img:first').stop().animate({opacity:1}, 1000);
        })
        $('.img_grayscale').mouseout(function(){
            $(this).stop().animate({opacity:0}, 1000);
        });
    });

    // Grayscale w canvas method
    function grayscale(src, index){
        var canvas = document.createElement('canvas');
        var ctx = canvas.getContext('2d');
        var imgObj = new Image();
            imgObj.src = src;
            imgObj.onload = function(){
                canvas.width = imgObj.width;
                canvas.height = imgObj.height;
                ctx.drawImage(imgObj, 0, 0, imgObj.width, imgObj.height, 0, 0, canvas.width, canvas.height);
                var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
                for(var y = 0; y < imgPixels.height; y++){
                    for(var x = 0; x < imgPixels.width; x++){
                        var i = (y * 4) * imgPixels.width + x * 4;
                        var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
                        imgPixels.data[i] = avg;
                        imgPixels.data[i + 1] = avg;
                        imgPixels.data[i + 2] = avg;
                    }
                }
                ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
                jQuery('.img_grayscale').eq(index).attr('src', canvas.toDataURL());
            }
    }