[Plugin: NextGEN Gallery] Some pics don't show in slideshow

I just added Nextgen and loaded 12 pics…works fine. Added 6 more and they do not show up in the slideshow. The thumbnails are there and I can pull them up from the thumbnails but they just don’t show in the slideshow. Need a fix please. Thanks.

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