My aunt left a heart on my girlfriend's photo

We had talked about not sharing photos with my girlfriend, but she posted something on her account. My aunt saw the photo and left a heart emoji underneath it. Moreover, she showed it to other relatives and asked, 'What do you think of her?' I felt both uncomfortable and didn't know how to tell my girlfriend. I'm worried that if I react to my family, my girlfriend won't like it. What can be done in such a situation?