How to delete phantom storage on iphone 5c?

[iMore Question]

I am having trouble finding a solution to my problem and need an good answer as to why my phone has roughly about 7 GB of phantom storage. My photos are not taking up a crazy amount of storage (only about 137 MB) and there is no sign of something taking up storage called "other." Also, my available storage seems to be fluctuating, sometimes by a few MB's and others by about 100 MB. Please help.

 

[Bigeric23]

This might be a good place to start:

https://support.apple.com/en-us/HT201656