A free program for Android, by WorkerBee App.
The Remove BG app is a handy utility tool that provides you with the necessary features to remove the background from any image. You can also use it to cut out photos in order to make them suitable for use as a background or wallpaper.
The app is capable of removing the background from both the regular photos and the ones that are in the format of PNG. You can choose between PNG and the JPG as the output format of the app.
The Remove BG app is very easy to use, and you don't need to have any prior knowledge in order to get started.
