Uses Apple's Core Image framework for photo proccessing. Supports iOS 11+. Instruments: Brightness, Contrast, Saturation, Sharpness, Vignette, Rotation.
Required iOS 13+.
Click one button and your photo will be automatically improved.
It doesn't matter what size of the imported image. But you can choose Full resolution when exporting.
Supporting languages: English, Russian, Japanesse.
You can use Camera, Photolibrary, or Unsplash (internet connection required) as image source.