Please see this FAQ which may help:
When I view my gallery, I see a blank area. Why?
In a Joomla environment, it can sometimes be difficult to know where the page containing your gallery's embedding code actually exists on your web server and, therefore, it would be difficult to point to your gallery folder using a relative URL.
Try using absolute URLs instead, for example:
<!--START JUICEBOX EMBED-->
<script src="http://www.example.com/images/jbcore/juicebox.js"></script>
<script>
new juicebox({
containerId : "juicebox-container",
baseUrl : "http://www.example.com/images/",
galleryWidth: "90%",
galleryHeight: "90%",
backgroundColor: "rgba(51,51,51,0)"
});
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->
... changing the two instances of 'www.example.com' in the above example to your own web domain name.
If you continue to experience difficulties, please post the URL to your web page so that I can take a look and help further.