Why does phone's storage say it's used 3G?

[Android Central Question]

I bought my aunt a Samsung J-3 a year ago. It only has 8 GB of internal storage so I bought her an 8 GB SD card. I set her phone up so all of her pictures would save to the SD card. Her phone keeps saying it's almost out of storage. Unfortunately, she lives in a different state so I was trying to troubleshoot over the phone. When I had her go into her storage it shows that for internal storage approx 3GB are for apps and approx 3GB are for photos/video. I had her look in her Gallery app to make sure all of her folders had the little SD card symbol and they do. I had her look in her Google photo app and make sure there was no space she could clear. I also had her go into "my files" and look under device storage in the DCIM folder and there is nothing in it. My aunt is an older lady and does not add apps to her phone or or do anything fancy with pictures. Anyone have any ideas on why her internal storage would say she's use 3 GB on photos videos when they are all stored on her SD card?

 

[Rukbat]

First, was she looking in DCIM in internal storage or on the SD card? (Device storage is internal - she should look in DCIM in SD Card.)

Second, if she takes enough pictures, even on a large SD card, it will eventually run out of free space. There's no such thing as infinite storage.

 

[dov1978]

If she's had the phone a year I would definitely recommend clearing the cache partition. The phone will have accumulated a boat load of junk files in a year and clearing that will definitely free up some much needed space.