<script>
var folder = "gallery-all/";
var photosRow = document.getElementById("photo-row");

var prefix = "<img src='";
var postfix = "'>";

$.ajax({
    url : folder,
    success: function (data) {
        $(data).find("a").attr("href", function (i, val) {
            if( val.match(/.(jpe?g|png|gif)$/) ) {
                photosRow.append(prefix + folder + val + postfix);
            }
        });
    }
});
</script>

<img src='gallery-all/img1.jpg'>
<img src='gallery-all/img2.jpg'>
<img src='gallery-all/img3.jpg'>
<img src='gallery-all/img4.jpg'>

"<img src='gallery-all/img1.jpg'>"
"<img src='gallery-all/img2.jpg'>"
"<img src='gallery-all/img3.jpg'>"
"<img src='gallery-all/img4.jpg'>"