Latest version is broken – how to revert?

Hi everyone,

I’m wondering if someone can provide me with instructions on how to revert back to NextGen Gallery 1.9.9? I’ve already downloaded that version, but don’t know how to do a “downgrade” to that version.

1.9.9 doesn’t work properly on my site – albums have disappeared and this unwanted slideshow has popped up on pages where thumbnails used to be.

Thanks in advance!

https://thealternativebride.com

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