1. A method for aligning an ordered stack of images from a specimen, comprising successive acts of: determining, for at least two already aligned images of the ordered stack, the respective misalignments with an unaligned image which is to be aligned next in the ordered stack; from the at least two aligned images, selecting as a reference image that aligned image with which the unaligned image has the smallest amount of misalignment; and aligning the unaligned image with the selected reference image.