If I am using Google Drive on a public Mac - it automatically has the tab of Google Photos there - and possibly able to be viewed by others and not vaulted/hidden. Will Cryptomator hide the photos in Google Photos to everyone, except me? Thanks!
I am not sure what exactly you mean by “Will Cryptomator hide the photos in Google Photos to everyone?”.
If you use the Cryptomator app for iOS or the virtual drive provided by the desktop application to add, store and access your photos they will not be readable in the Google Drive app.
If you add the photos to Google Drive directly, by using the Google Drive app they will be added unencrypted and show in Google Drive and Google Photos. Cryptomator can not interfere with the way the Google Drive app or in general other apps work. If you want your files to be encrypted you will have to add them to a Cryptomator vault using the Cryptomator app or application.