Apple-E or Alt-E
Sometimes when you do this, depending on the type of layer blending modes you’ve set, your result will not be as expected. If this is the case, simply flatten your image (or if that still yields a strange result), save the image as a TIFF or JPG (which will automatically flatten the image AND retain the look).
https://www.youtube.com/graphicsdump
https://www.myr3d.com