first, the app has functions of crop, rotation, share, set as wallpaper.
And while editing photo, and when you want to go back to original picture, surely rollback function provided.
when you save your photo, you can save the photo with quality you want.
And when you save your photo in your photo, you can save to the place you want manually or the designated place(/photo size).
Lastly, speaking of setting as wallpaper, you can do with the mode(fit to width, fit to height, fit all, no fit).
Surely simple but powerful.