My folks did the same thing...and "back in the day" the photos would have the date printed on the back of the photo..I dunno, but folks from that generation, and older often wrote on photographs about who and sometimes when. My grandma was an avid photo taker, and thank god, she wrote who folks were, even if it were her. Those photos have been passed on to me (my dad is dead). No chance I would recognize my grandma as a teenager unless the photo told me so.
Now, if she had simply wrote "me".....hmmm. Not sure how that would translate.