Broken Links

Hoping you can help me out here. I’m not certain if it is actually an issue.
I ran a few checks on my site to see if any improvements were needed anywhere. Things such as load speed, readability etc.
One check was for broken links.
I found a few and fixed them but these last three have me beat and they all appear to be regarding my gallery.
Is there anything I can do to fix this?
The gallery seems to be working just fine by the way.

404 http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/assets/assets/images/blank.gif
style: #prevLink, #nextLink http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/includes/../assets/style/lightbox.css?ver=4.9.2

404 http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/assets/assets/images/prev.gif
style: #prevLink:hover, #prevLink:visited:hover http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/includes/../assets/style/lightbox.css?ver=4.9.2

404 http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/assets/assets/images/next.gif
style: #nextLink:hover, #nextLink:visited:hover http://catparksaustralia.com/wp-content/plugins/portfolio-gallery/includes/../assets/style/lightbox.css?ver=4.9.2

Regards
Jim

The page I need help with: [log in to see the link]