The development of this feature was spotted in the WhatsApp v2.20.199.5 beta for Android. This feature, as earlier stated, is still under development, and will not be available to users even if they are using the beta version. It is expected to rollout in some future beta version, before it then gets released to the general public.
A report by WABetaInfo says that when users want to choose a default wallpaper in the app, it will ask if they want to download the WhatsApp Wallpaper App. This app lets them select different wallpapers for the chat app’s background. It is believed that once the new feature is official, the wallpaper app will be updated with more options for users to choose from. WhatsApp is also said to be working on a Storage Usage redesign. This section will have a new storage bar at the top with details showing the space taken up by media files shared over the app. A Suggested clean up option will also be available. This will list forwarded and large files in a thumbnail view to help users review them and delete them if need be. This feature is still under development and has not yet been enabled for WhatsApp beta users. References
