Manage iPhone 7 storage

A) Have you deleted the photos/videos from the Recently Deleted Folder?

Delete photos permanently 

If you want to permanently delete your photos or videos within 30 days, you can remove them from the Recently Deleted album. When you delete a photo from this album, you can't get it back.

1. Open the Photos app and go to the Albums tab.
2. Open the Recently Deleted album and tap Select.
3. Tap each photo or video that you want to permanently delete.
4. Tap Delete and confirm that you want to delete the photos.

B) Have you emptied Recently Deleted Folder on Files

1. On iPhone, launch Files app
2. At the bottom, click Browse
3. Select Recently Deleted, under Locations
4. Delete the items here, if not required

C) Have you emptied Recently Deleted Folder on Notes

1. On iPhone, launch Notes app
2. At the top left, click Folders
3. Select Recently Deleted
4. Delete the notes here, if not required

Also, please see: How to check the storage on your iPhone