Yes you can use WhatsApp to compress images and videos
Instant messaging services, like WhatsApp, compresses photos and videos to reduce bandwidth and quickly send the files. That is why we can use it to compress these file types. WhatsApp works great if you don't mind the loss in quality.
Follow the steps below:
Send the set of pictures and video files to one of your friends (or yourself) via WhatsApp.
Go to the WhatsApp Media folder on Android or your Camera Roll on iOS to find the compressed versions.
Delete the originals if you want to save space.
How to find the media files on Android
SD Card root directory showing the WhatsApp directory (tap it to open)
You will see all media types stored in WhatsApp folder.
Now, you just need to tap the appropriate folder to get the compressed version of each file set via WhatsApp as explained above, ie,
Images folder for Photos or images
Video folder for video files
Audio folder for music, recorded speech, etc.
If you don't mind the loss in quality and or if you wish to save space on your device, you can delete the original files.