че уж там
<ul class="photos-list" id="photos-list">
<li><span><img src="image/1.jpg"></span></li>
<li><span><img src="image/2.jpg"></span></li>
<li><span><img src="image/3.jpg"></span></li>
</ul>
<script>
var elems = document.getElementsByTagName('img');
var arr = Array.prototype.map.call( elems, function( img ) {
return img.src;
});
alert( arr.join( '\n' ) );
</script>