Hi there, @Monika 
I am glad to say that it’s possible to achieve this using our Photo Gallery app!
Firstly, you should add photo categories (folders) in the widget editor:
Then you should manually assign these categories to the photos:
To let users switch categories, please enable Filters on the Layout tab:
Unfortunately, it’s impossible to assign categories to multiple photos right away, but this idea is already on the Wishlist. Feel free to upvote it 
- Bulk Assign categories to photo