Start by switching your Wi-Fi router off and then back on.

If other applications are also experiencing similar connectivity issues, check that you're connected to the internet. You can also try visiting a webpage on your preferred browser.

Try using other apps on your phone and check if they can access the internet. This could be the reason why your WhatsApp images are not downloading. When you're having difficulties using an app that requires an internet connection, you should check that your Wi-Fi or cellular data connection is working correctly.