I'm not really seeing a problem with your web page.
When I narrow the browser window, the gallery's width reduces dynamically to fit the new viewport width but the gallery is always visible in its entirety. The vertical scroll bar never obscures the gallery, no matter how narrow it is. (I have viewed your web page in Chrome, Firefox and Internet Explorer on PC.)
Please let me know what browser(s) you see the problem in and, if possible, please upload a screenshot somewhere so that I can see what you are seeing.
There are a few things I have noticed on your web page which might help, though:
(1) You currently load the 'juicebox.js' file three times on your web page.
The 'juicebox.js' file should be loaded only once per page (regardless of how many galleries you have embedded on the page).
Try deleting two of the following lines of code on your page:
<script src="needleFeltAnimals4/jbcore/juicebox.js"></script>(2) You currently set your gallery's width to be:
galleryWidth : '',Using an empty string for the gallery width will probably default to 100% but, to be sure that the gallery is using a 100% width, use the following instead:
galleryWidth : '100%',(3) The Doctype Declaration should be at the very top of your web page. Currently there is a blank line (whitespace) above it.
This is unlikely to be causing any problems and browsers will probably overlook it but, strictly speaking, it should be the first thing in the document.
(4) Try checking the code on your web page with the W3C Markup Validation Service and fix the errors reported.
https://validator.w3.org/
Once the code on your web page validates correctly, the page should be rendered with greater predictability and consistency across different browsers.
I hope these notes help.