Thanks for the reply. It was config.xml but what was happening, Chrome for some reason was caching the older version and did not reload the updated version even with hared refresh. Had to go to network debug tab and clear cache on the file manually for it to take :) Appears to be working fine now as expected.

Version pro_1.5.1.2 Tested with a simple page using Flickr integration. 

When specifying thumbsPosition: 'BOTTOM', or 'TOP' the thumbnails display vertically and the main image does not display at all. When clicking on next / prev arrows or thumbnail it does nothing. Using 'LEFT' or 'RIGHT' works fine as expected. No console JS errors. See attached image for how it renders.

Is this a known bug?

Code used for testing, nothing else on the page:

<script>
new juicebox({
    containerId: 'juicebox-container',
    flickrUserName: "*****",
    flickrTags: "Ultimae",
    thumbsPosition: 'BOTTOM',
        showOpenButton: 'false',
         useFullscreenExpand: 'true'
    });
</script>

<div id="juicebox-container" style="margin: auto;"></div>