You see how the final photo on the right is rotated a bit? That's because PSE attempts to align the two photos in order to ensure any portions you merge stay aligned from photo to photo. As I look at the positions of the children's heads from photo to photo, it looks pretty good. But if the photos do not align well, you can use the Alignment tool to map marker points. It might be hard to see here, but I moved the three marker points around my son's head—one each on his shirt where the sleeves meet the collar, and one at the top of his head. (Click the image to see a lareger version)
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