Hi!
I have installed your extension with Joomla v3.3.6 and it worked nicely with the option "Do not load jquery library" because Joomla had already loaded jquery:
<script src="/joomla/media/jui/js/jquery.min.js" type="text/javascript"></script>
....
<script src="/joomla/plugins/content/jw_sig/jw_sig/includes/js/jquery_fancybox/fancybox/jquery.fancybox.pack.js?v=2.1.5" type="text/javascript"></script>
I upgraded Joomla to v3.4 and when I clicked to a thumbnail, it opened a new window with the image.
I saw in the html source code that Joomla had the jquery loading line after SIG:
<script src="/joomla/plugins/content/jw_sig/jw_sig/includes/js/jquery_fancybox/fancybox/jquery.fancybox.pack.js?v=2.1.5" type="text/javascript"></script>
...
<script src="/joomla/media/jui/js/jquery.min.js" type="text/javascript"></script>
So, I went to SIG options and selected to use jquery v1.11 and now the jquery loading line comes before SIG just ike Joomla v3.3.6.
But why would that happen? I mean, since Joomla loads jquery, why is SIG loaded before jquery in Joomla v3.4?

Hi,

It doesn't matter which version you select there. The plugin will detect that you are under Joomla! 3.x and will use the system's jQuery, it will not load an extra instance. I made several tests and it works as expected. The ordering of the scripts depends on the extensions and your template.