I'm selling my iMac so I'm cleaning it out. I deleted all of my photos from Mac OS Photos (after removing my iCloud account). Is there an empty trash or are they completely gone now?
If you don't at least delete your existing account from the Mac, you should follow these instructions if you are selling it - reformat the storage and install MacOS from scratch so all of your existing information is gone: How to reset your Mac before selling it | iMore