Why all the looping to add elements?
$('#imgSection').append("<div>" + displayArray .join("") + "</div>");
Okay so it is elements.
The quickest way is going to be using append with the array itself.
$("#out").append(elems);
other option using one div to append is
var div = $("<div/>").append(elems);
$("#out").append(div);
BUT appending a lot of images at once is going to be bad unless they are preloaded. That will be a bunch of http requests being queued up.