https://play.google.com/store/apps/details?id=org.indywidualni.pictureflip
Most camera apps take flipped selfies. Why? Because they are supposed to look like another person was looking at you. Some people don't like it so there is a nice app to flip your selfies and all the JPG images easily.
Flip a picture vertically & flip a picture horizontally.
The app keeps the quality of all the images.
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Important: In order to build the project Firebase config file is needed (/app/google-services.json)