Start the Finder and go to your user directory and open the folder called “Images”. When the Pictures folder opens, you should see a library file called “Photo Booth Library”. The PhotoBooth library is located inside the Pictures folder of the home folder. I want to automatically backup photos and videos from the photo booth to Google Photos, but I don't know where they are stored.
In that sense, package files for Photo Booth are very similar to the original file library with the Photos application on the Mac, both accessible to users, but usually hidden from the average public through the file system. Any of these Finder locations can be accessed directly from the Finder or Terminal, but keep in mind that if you move files out of those directories, they will no longer appear in the Photo Booth app on your Mac. Every time you capture an image or video in Photo Booth, those images are stored in a special file in the Photo Booth library stored inside the Pictures folder. You can also drag and drop individual images from the small Photo Booth image bar to the desktop or into a folder and save them individually outside of Photo Booth as a generic JPEG file.
These are the original image files, so if you delete them from this folder they will no longer appear in the Photo Booth application on Mac OS X. Perhaps the best way would be for your Photo Booth application (or whatever you use to take photos) to direct the files saved in a file folder in the cloud such as DropBox or even iCloud Drive. I suspect that it is the file system lock introduced in BigSur that now prevents everyone from accessing their own photos. This will create a folder called PhotoBoothPics that is a link to the photo booth library, and is accessible to attach to email, etc., and it will always have all your photos.