Constant decrease in android's internal storage free space I am having a hard time with my phone. My device, which is a simple LG Magna has had a constant decrease in FREE space. That means that something is constantly taking up more and more place in my internal memory. Of course, I did try to clear cache, clear all the useless videos, useless apps, I removed the Facebook app because I know it uses a lot of space, but the used space in the internal memory keeps on increasing. My 8Gb internal memory is already used up by 7.97Gb. And I deleted so much already on my phone.. Okay! I thought about the possibility of having a virus in my android. 

So, I did factory reset my SD card and Internal memory. This means, starting every from back to square one. I managed to not download anything from the internet, use only the useful apps from the store like Whatsapp, Facebook Messenger, my usual music player which is BlackPlayer(Great app btw, try it, it's simply the best). Now, 2 weeks after the factory reset, I am surprised and also very annoyed to see that the device's internal memory is increasing again. Today, it is back to 7.97Gb. 

I have only photos and merely some music on my phone.

Basically, I have absolutely NO free space on my phone and I can't never delete enough to free space.
Can someone please help me resolve this problem? I would be forever grateful!
Thanks in advance.
Seeing the reference to WhatsApp... I installed All-in-One Toolbox today for another problem (https://play.google.com/store/apps/details?id=imoblife.toolbox.full&amp;hl=en). I happened to notice it has a cleaner just for WhatsApp.