1. A method of processing images that are arranged in a first series of biological images and a second series of biological images, each image being associated with a respective axial slice height, the method comprising: a) initializing a threshold slice height difference; b) attempting to identify one or more pairs of corresponding images such that (i) each pair of corresponding images includes one image from each of the first and second series and (ii) the images in each pair are associated with respective slice heights differing by no more than the threshold slice height difference; c) increasing the threshold slice height difference; d) repeating steps b) and c) until the threshold slice height difference reaches a maximum threshold slice height difference; and e) for particular images in the first and second series that have been paired further to execution of step b), displaying each particular image in the first series in graphical correspondence with the particular image in the second series to which it is paired.