[Plugin: NextGEN Gallery] Nextgen image title or tag searcheable by wordpress?

Hi Im using nextgen with slimbox2 on this website https://sugarcastles.com/wordpress and I would like the image titles or tags to show when someone types them into the websites search bar. (e.g. fondant) They show in the page source but they wont return in the search results. Can anyone tell me how to do this? Thank you.

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