As it stands, you say this posed picture indicates to you that Manning wasn't that frail, and looks smiling and happy. If it is placed here to put the lie to the text and sources about aspects of her past, then it is arguably not neutral, however cute. I wouldn't support having a picture of Kissinger smiling and joking next to text that described him as being in serious wartime negotiations. I'm not saying the picture is objectionable in and of itself, I'm saying (pending a chance for arguments for its inclusion) it makes the article less unarguably neutral. If the picture causes you to say that the text overstates her height issues, health issues, level of childhood happiness etc. then it is arguably not an appropriate image based on the text and sources describing her past. __