hobo,
или так
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>demo</title>
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script>
$(window).load(function(){
var img=$("#sbor li img"),
imgarr = $.map(img, function(el){
return $(el).data('img');
})
alert(imgarr)
});
</script>
</head>
<body>
<ul id="sbor">
<li><img src="/img/a/b/1.jpg" data-img="1.jpg"/></li>
<li><img src="/img/a/b/2.jpg" data-img="2.jpg"/></li>
<li><img src="/img/a/b/3.jpg" data-img="3.jpg"/></li>
<li><img src="/img/a/b/4.jpg" data-img="4.jpg"/></li>
<li><img src="/img/a/b/5.jpg" data-img="5.jpg"/></li>
</ul>
</body>
</html>