Setting a featured image

I have noticed a problem when editing a post in WP and trying to add a NextGen featured image. I click on the link to open the pop-up window and select the gallery.

Not all the photos are listed here, and when I try to click on the next page or the “next” button, nothing happens. You can also see the first image is not lined up with the others. This is from Safari, but I’ve also tried this on the latest version of firefox and chrome and it behaves the same way.

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