The current implementation (0.6.3) requires you to open the filter view from menu or toolbarbutton. If you enter a text into the "Find" field all photos that contains searchtext in path, filename, title, description or tag will be shown.

The searchbar in my app could have the same funtionality. and is much more easy and intuitive to use.

Inspired by
https://www.reddit.com/r/androidapps/comments/8335dy/looking_for_galley_app_for_pictures_that_has_a/