Yes, Terry, That's the right page. I just looked to get the exact language for you. On the left side, under the "Add a Comment" section you will see "Edit Image Details". Under that is "Image Title" and under that is "People and Things in the Image". That's the section you want. There is a listing for Nancy Winchester that has 3 of those little circles (they're called "radio buttons") named uncertain, certain, and REMOVE from Image. You want to click the one for REMOVE from Image to color it black. Then scroll all the way down to the bottom of the page and click the big green button named SAVE CHANGES TO IMAGE DETAILS.
It looks like it's slightly different from how I originally remembered it - when I said there was a radio button that you could un-color, I was wrong and I apologize for having further confused you with something that's not there.