<img class="comment_pics" width="50px" height="50px" src="img/01.jpg"/>
 
<div class="bg">
    <img class="bgImg" style="max-width: 100%; max-height: 100%; position: fixed;" src="">
</div>

.fillbg { background-color: rgba(0, 0, 0, 0.6); bottom: 0; height: 100%; left: 0; opacity: 0; position: fixed; right: 0; top: 0; width: 100%; z-index: 1100; display:none; }
.fillbg-active { opacity: 1; display:block; }

<script>
    var newImg;
    var clientH=$(window).height();
    var clientW=$(window).width();
    var w = '250';
    var h = '250';
    $(document).ready(function(){
        $(".comment_pics").bind("click", function(){
            newImg = $(this)[0].src;
            $("body").append('<div class="fillbg"></div>');
            $(".fillbg").addClass("fillbg-active");
            $('.bgImg').css({'width': w+"px",'height': h+"px",'top':(clientH-h)/2+"px",'left':(clientW-w)/2+"px",'z-index':1101});
            $('.bgImg').attr("src",newImg);
        });
        $(".bgImg").bind("click", function(){
            $(".fill-input").removeClass("fill-input-active");
            setTimeout(function(){
                $(".fillbg-active").removeClass("fillbg-active");
                $(".fillbg").remove();
            },300);
            $('.bgImg').css({'width': '0px','height': '0px'});
            $('.bgImg').attr("src",'');
        });
    });
</script>