The Storage tab does not always report correctly. Look in About this Mac > System Report > Storage. It may be different. As Klaus says, try rebuilding Spotlight index.
How to rebuild the Spotlight index on your Mac - Apple Support
Omni DiskSweeper can locate and delete those files. It can also give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. Itcan show you the precise size and location of all your files. It will inventory your disk starting from the files that take up the most space. It can also give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. If you want you can even delete files from OmniDisk Sweeper. But be careful some of the items may be important to your system.
For information about the Other category in the Storage display, please see Apple Support Topic
https://support.apple.com/en-us/HT202867
Also, empty the Trash if you haven't already done so. If you use iPhoto, empty its internal Trash first:
iPhoto ▹ Empty Trash
In Photos: File ▹ Show Recently Deleted ▹ Delete All