As of 27th November 2017, you can also use Photo Mate R3 as a free version with a limited feature set.
The free version includes all the features from the full version except:
- Luminance and Sharpening
- Layer editing (Gradients, Brushes, Lasso and more)
- Custom export presets
- Organize and filter your images in a library
- Batch renaming and batch export
- Custom watermarks
- Display calibration
The free version also uses ads to support further development and needs an internet connection when you enter the editing mode.
Note: The free version requires Android 4.4.4 (KitKat) or newer!