One of the biggest problems using WhatsApp is how WhatsApp uses the internal storage of Android.
Everytime you send an image, video or an audio file. WhatsApp creates a copy of it in the media folder.
After a period of time this folder becomes bigger and the Android system starts hooking.
WhatSentCleaner is the free solution!
Just check the checkboxes and with a click on the clean button the unused copys will be deleted an your internal storage gets new breath!
The app is free - so if you like it feel free to share ;-) - http://www.smartphonehilfe.de