A free app for Android, by AA2G1 Studios.

Photo by Number is a fantastic photo editor app. With this app, you can transform your photos into beautiful pixel artworks in seconds! This application is the best and most convenient tool to create pixel art. It has various options for you to edit your photos, including different types of images and sizes. You can also use your own images or choose from the various images in the app. The app has an option to choose the number of colors for each image. 

You can also edit the colors, change the brightness, and choose from a wide variety of pixel art effects.