Photos deleted - but still showing on the internal drive

HELP - I'm helping a friend with her MacBook Air but I have run into a storage issue.

I have saved all the images/videos from the Photos to an external USB. Then deleted the photos from folder and have deleted them from the trash. BUT the internal drive is still showing 32 GB of space used for Photos. Then when I go to the photos - there is nothing there.

This all started so that I could upgrade the macOS to the Catalina 10.15.6 because it would not allow due to unavailable disc space. I managed to upgrade the macOS. But still the storage is showing 32 GB of photos - that are non existent on the MacBook Air. I have since restarted the Air to see if that would correct the issue, but it has not. Help - she will be traveling and will have very limited access to wifi/internet, so we are trying to free up space so that she does not run into any issues with her Air running out of space while on her adventure!!!