Doing so will place a “Click to Name” circle on my image. What I’ll do, then, is click the “Add Faces” plus button within that info window. …I find that there aren’t any faces listed. I can tell that Photos doesn’t recognize who’s in the picture because when I click the “i” icon in the toolbar to get info on the image… For this, you’ll start with the uncategorized image. In that case, you’ll need to manually add that picture to a person’s “Faces” album, but luckily, it’s pretty simple to do. But sometimes, Photos doesn’t recognize that there’s even a person in an image you took. Photos on the Mac does a great job of picking out faces, and if you’ve gone through and categorized the folks you know, it’s a handy feature for finding snapshots of your great-aunt Mabel (or whoever) without having to scroll by date.