It seems to me that the way you SELECT images in Aperture determines the order in which they will be exported. What I see is that many people select images by pulling their mouse from e.g. right-below to top-left. So the first image selected is the the one the mouse encounters first and is the one right-below. When you give the exported files a counter, then that one will get 1. And so on. What works is this: - select e.g. your album in Aperture - arrange the images the way you want e.g. by Date - make sure no image is selected - from the menu choose Select All (or Cmd-a) Now when you export with a counter, the files are numbered in the exact order you have chosen for them in Aperture.