Need to translate this sentence(got the language pack)

I downloaded the language pack and almost everything works but 1 sentence that can be found here
https://www.jukeboxheroes.nl/foto?album=1&gallery=1

For some reason it didnt translate show as slideshow whilest it is in the language pack.

how can i change this manualy?

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