A free app for Android, by Smart Theme.

This is the most popular customizer for Xiaomi mobile phones, which is made for the Xiaomi MIUI operating system. It is made up of a list of themes, wallpapers, icons, and a lot of other things. All of these can be downloaded for free in the app and you can also get new themes every day.

All of these things are made up of HD pictures and they are optimized to be as small as possible. The application is easy to use, just install it and open it. You will see the main screen, where you can choose between different themes and wallpapers.