WhatsApp became an important part of our daily life. People also use this app for their needs like sending photos and videos to somebody. Sometimes we receive the photos on WhatsApp but that doesn’t save in the gallery. If your WhatsApp pictures not showing in gallery then try these methods:
1. Make sure you have allowed WhatsApp to access your gallery
2. Enable the WhatsApp images to save to the camera roll from WhatsApp settings
3. Restart your WhatsApp again
4. You can manually save the photos in the gallery
Source: https://getassist.net/whatsapp-images-not-showing-in-gallery/