Nikon D90 - Image Overlay

Image Overlay
Image overlay combines two existing NEF (RAW) photographs to create a single
picture
that is saved separately from the originals; the results, which make use of RAW
data from the camera image sensor, are noticeably better than overlays created in an
imaging application. The new picture is saved at current image quality and size
settings; before creating
an overlay, set image quality and size (pp. 62, 63; all options
are available).
To create an NEF (RAW) copy, choose an image quality of NEF (RAW).
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