I have many many photos on a very old version of iPhoto (pre 9.0) that's proving a pain to upgrade into Apple Photos on El Capitan.
Question is - can I simply copy the "Originals" and "Modified" folders that are inside the iPhoto Library out into the Pictures directory itself, and then import these into Apple Photos directly?
EDIT
Also - if I do this, will the copy necessarily take up twice the space in my hard disk, or will disk level de-duplication help to reduce the disk used? If it takes up twice the space this may not work as the photos take up more space than I have free at the moment.