In your gallery's 'config.xml' file, you currently specify the backButtonUrl and splashImageUrl with absolute paths using http:// rather than https://
Change your paths to use https:// or scheme-relative URLs (starting with //) instead.
For example, change:
splashImageUrl="http://www.countyfairgrounds.net/images/139_10.jpg"
to either:
splashImageUrl="https://www.countyfairgrounds.net/images/139_10.jpg"
... or:
splashImageUrl="//www.countyfairgrounds.net/images/139_10.jpg"
Also, in your gallery's embedding code, change:
<script src="/jbcore/juicebox.js"></script>
... to:
<script src="//www.countyfairgrounds.net/jbcore/juicebox.js"></script>
I notice that you have other http:// links in your web page (in your <div id="sociallinks"> container) that you may also need to change.