Using PhotoSwipe with prettyPHOTO gallery

Dear Photoswipe community,
I recently enabled a very effective prettyPhoto lightbox slideshow that launches from a thumbnail as per the excellent instructions on this thread https://www.ads-software.com/support/topic/plugin-nextgen-gallery-nextgen-gallery-open-album-in-lightbox?replies=75

However, when I view it on my iPhone it displays
“Fatal error: Call to undefined function ngggetgallery(“
even with Photoswipe for NGGallery installed. In fact, I can’t seem to get this Photoswipe plugin to have any effect. I am using this for my professional site and I would love some advice.

My slideshow is running at this site under the “About” tab.

Thanks in advance!
Ethan

https://www.ads-software.com/extend/plugins/photoswipe-for-nextgen-gallery/