Hi, it's there's an issue while working with small image and juiceBox, I just came across with and I hope I found a solution to this. All image work fine under juiceBox until I add small image.
this is an example (I'm using the pro version therefore I can't create a page with sample) though here the snippet (the following has 2 small image 4 and 5 if you hot the next button/arrows)

<script>
            new juicebox({
                containerId: 'juicebox-container',
                useFlickr:true,
                flickrUserName:'winehook',
                flickrSetId: '72157622836259260',
                flickrShowTitle: true,
                flickrShowDescription: true,
                flickrShowPageLink: true,
                flickrPageLinkText: "Tada!",
                shareFacebook: true,
                shareTwitter: true,
                backgroundColor: "#ffffff",
                galleryWidth:'600',
                galleryHeight:'400',
                showThumbsOnLoad: "false",
                galleryTitle: "M. Shanken Image Gallery",
                showImageOverlay: 'ALWAYS',
                galleryTitlePosition: "NONE"
            });
        </script>
when I load the page this error show:
undefined:1 GET http://mshanken.dev/undefined 404 (Not Found)

When I land to the missing image this shows:
VM28873:1 Uncaught TypeError: Cannot read property 'toLowerCase' of undefined

Can you help, please. Thank you!