Reducing file sizes **decreases** available space

[kenppy]

I'm trying to increase working disk space.
To do this I reduced a few hundred jpgs using Preview to resize and reduce the resolution, in all reducing the folder size by 0.5GB. But the available space has now reduced ! The files were overwritten and no copies made -- I can now see that all, rather more than all I saved has gone into Other.
I've restarted and it's still the same.

Is this some temp working, how do I resolve this? Top image is after.
thanks

 

[Fishrrman]

My opinion (and mine only) is that the information you see in that box can be unreliable, and sometimes totally inaccurate.

To get a clearer picture of what's using up your space, try DiskWave (small app, free to use):
https://diskwave.barthe.ph

Just launch it -- you'll see what to do next.
HINT: set the preference to make normally-invisible files VISIBLE.