Many people have problem with their handphone while using WhatsApp. It's because WhatsApp automatically download photos and videos to their handphone. Many people have their handphone hang because their memory is full.
To prevent the memory from out of space because of Whatsapp, just stop the Automatic Download from WhatsApp.
Then click "Chat settings"
Click "Media Autodownload". Make sure they are off or unchecked.
You have to make sure "No Media" is below all the 3 modes. You have to click each mode and unchecked the Images, Audio, and Videos as below:
You do it again for the rest of the modes and don't forget to click OK.
Well, your WhatsApp will not download the Images, Audio, and Videos automatically so your memory is safe. If you want to save the Images or Videos, just click at the Images or Videos.