Image: Telegram
You can now use your favourite photos or colour combinations as custom wallpapers on your Telegram chats. When you set the wallpaper, a prompt will be sent in the chat that lets your chat partner use the same wallpaper, or they can opt to choose one on their own.
To set a custom wallpaper, tap > 'Set Wallpaper' in the chat header on Android or open a profile and tap > 'Change Wallpaper' on iOS.