How does WeChat set the theme background wallpaper?

Wechat can set the theme background wallpaper as follows:

Operating environment: Huawei Nova8, EMUI 1 1, WeChat 8.0.0.

1. On my page, click Settings.

2. Next, click Chat.

3. Then click on the chat background.

4. According to your own needs, you can choose the pre-stored background of the system, choose from your own photo album, or take photos now.

5. Finally, check the picture that needs to set the background picture, and the setting will be successful.