sm-g920f stock gallery (problem?)

Hi all,

First question :p
In the stock gallery app, there is a option to sort it by category.
then there is a album with "food" and "environment" with pics inside. And most of the time it really is food or something with environment.
How does it detect it? Does it send the pics to samsung server to get recognized?! Dont want my pics on the server of samsung...

Second one,
when i open gallery app and go to a random album with a lot of pics, when i flick it really quick it goes damn slow. Its like there is a brake on it.

Thanks for helping me out!

How can i unroot my galaxy S6 SM-G920F

Hi guys , Plz i really need to know how to unroot my galaxy S6 without touching my photos and musics ( if it's possible ) , thank's for your answer