IMG files on Tab S2 Lollipop 5.0.2

Hi. If my only purpose is to look through the city maps because the screen is bigger than my GPS, what Android app should I use?

The idea is just an img viewer. NOT a GPS navigator.

I want to use the tablet as a city guide for Russia using the Russia NT 2017.10 Navicom img file.

As far as I understand OruxMaps and Streetpilot for Android can do the trick, but maybe they are too much for my purpose.

Tab S2 Lollipop 5.0.2

Thanks in advance

*I will carry my Garmin device too.