The effect is sometimes called "The kid stays in the picture" effect taken from the technique used in a movie. It's also called camera mapping and a bunch of other things. It's not really the "Ken Burns Effect" a name given to the technique of doing camera moves on still images. Ken didn't invent it by the way, it's been done since movies were invented, Ken just did it well in his first PBS historical series so folks without any knowledge of film history credited him with inventing the technique.
Enough on that. To create the effect you need to separate the foreground, middle ground, and background elements from a photo. That usually requires duplicating the original image layer in Photoshop, masking the duplicate, then filling in the hole left by removing the foreground in the background of the image. Once you have a layered Photoshop file you bring the file into AE and make all the layers 3D, separate them in Z space, scale up the background layer to fill the frame, and then add a camera. You animate the camera. There is a limit on how much camera movement you can get away with. A little experimenting will let you know when you've got it right.
There is at least one 3rd party plug-in that kind of automates the process. It's doing exactly what I described all inside AE though. The effect is also easily reproduced in 3D apps using projection mapping. It's still the same trick. You separate out foreground, middle ground, and background elements from a still image, arrange them in 3D space, then move a camera through the space.