The code is from Addy Osmani: Learning JavaScript Design Patterns, and I didn't really get the implementation.
I may be blind here, but I can't see what's wrong with this:
ReferenceError: Can't find variable: items
Underscore template:
<script id="resultTemplate" type="text/html">
<% _.each(items, function( item ){ %>
<li><p><img src="<%= item %>"/></p></li>
<% });%>
</script>
jQuery:
var resultTemplate = _.template($("#resultTemplate").html());
[...]
Demo: jsFiddle
items?