If you used effects on an image, the unmodified version is located in the Originals folder. You can export photos and videos for use in other applications. Single and 4-copy photos are exported as JPEG files; video clips are exported as MOV files. You should now be able to see all the photos you have captured with the photo booth app on your Mac.
That didn't help, but Apple Care found the answer for me, so for those who might be interested, video files for Photo Booth can be found in iMovie or Movie. The Photo Booth window appears, showing all images captured as thumbnail images at the bottom of the window. I see all Photo Booth photos and videos on my screen, but I need to find the files before I can publish them. I suspect that it is the file system lock introduced in BigSur that now prevents everyone from accessing their own photos.
Photo Booth (well, or just a “photo booth”) is a great standard macOS application that allows you to take a snapshot or record a video from a FaceTime camera located on a MacBook or iMac. As for automatic backup, there is no direct way to do it, since Photo Booth doesn't have many options for it. Photo Booth is a photo taking application that comes pre-installed on all Macs and is not a common application to take pictures. This is how easy it is to access the photos that were taken with the Photo Booth application, a task that once seemed difficult is now much easier to perform, all thanks to Finder and its incredible functions.
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. You can also use symbolic links to achieve this, by linking the Photo Booth app directory to the DropBox folder, or whatever. Perhaps the best way would be for your Photo Booth application (or whatever you use to take photos) to direct the saved files to a file folder in the cloud such as DropBox or even iCloud Drive. I want to automatically backup photos and videos from Photo Booth to Google Photos, but I don't know where they are stored.
I thought that photos or videos were archived as soon as you made them, but that you could also send them anywhere you want. After you install the app and sign in to your Google Account, you can select the folders that Google Photos will automatically back up. 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.