Here's a photo of her back: https://i.ytimg.com/vi/KZZvVl11PvU/maxresdefault.jpg. This is the life-long damage: http://img2.timeinc.net/people/i/2015/news/151109/napalm-gir....
The flame and smoke from the napalm attack that all the people in the picture are running from is pretty much the whole background of the picture, though the fact that its black and white and the cloud is fairly thick may make that less immediately recognizable.
> but I've been told (since junior high school) that it is a picture of a burning child.
Its not a picture of a child in flames [0], though its picture of a child experiencing burning as a result of the napalm drop (according to her, her recollection is that she was screaming "too hot, too hot" at the time the photo was taken), and the absence of visible flame isn't the same thing as the absence of continued burning.
[0] Well, not the child that's the central feature of the photograph. There are children burning in that sense as well in the picture, I suppose, if you consider the background and what is actually burning there.
Besides, burning does not require fire to be present. It only requires heat (or chemical reaction).
Common sense tells me that the child's clothing was on fire, and she took those clothes off and ran away, and that's what we see a photo of. Fine.
But then... why is this photo described as a picture that contains flames? Not just here. That's always how it is described.