One of the easiest ways to make a chat stand out is to use a unique wallpaper. That way, you will not end up sending messages to the wrong people. See how you can set your own wallpaper for individual WhatsApp conversations on iPhone and Android.
If you want you can put your own wallpaper in a chat. You can choose one of the built-in WhatsApp options or you can use your own photo.
Unlike Instagram, WhatsApp's custom wallpaper feature is not synced to all users. Therefore, both parties can have their own custom wallpaper for the same chat.
Set your own WhatsApp chat wallpaper for Android
To get started, open the WhatsApp app on your Android smartphone. Here, go to the "Chats" section and open a chat on WhatsApp.
Press the menu button from tool bar and select "Wallpaper".
Here, you will see some choices called "Bright", "Dark", "Solid Colors" and "My Photos".
Browse photos and tap a photo to preview.
Then click on "Set Wallpaper".
From the pop-up dialog, make sure you have choose select "For This Chat" and press the "OK" button.
Chat wallpaper updated. If you want to remove the custom wallpaper, click on menu, go to the "Wallpaper" section, press the "Change" button, select "Remove Custom Wallpaper", then press "Remove" to confirm the change.
Set a wallpaper in WhatsApp chats for iPhone
Here, select "Wallpaper & Sound".
Now select "Choose a New Wallpaper".
Once you are satisfied, Press the "Set" button.
Now, go back to the chat and you will see the new custom wallpaper directly in the chat background.
If you want to remove the custom wallpaper, go to Wallpaper & Sound> Choose a New Wallpaper and click "Remove Custom Wallpaper". Then select the "Remove Custom Wallpaper" button for confirmation.
Source of information: howtogeek.com