WCleaner is a little tool that deletes with one click all images you receive by WhatsApp and are showing on Gallery althought you don't want.
It is free!
You can delete all files, only images, audio or video, or select what files you want to.
You can see more on Google Play.
Download it here:
Any bug, problem or question, please feel free to contact me by email.
Thank you very much and sorry for my english.