So after the iPhotos library is migrated into the Photos Library can I delete the iPhoto library? And how do I do that? It shows up in document usage but not in applications. It seems I am taking up a lot of memory with duplicate photo files.

I would keep a copy of the iPhoto Library on an external drive, just in case you are noticing any problems later. You cannot be sure, that all photos have been migrated correctly, unless you have viewed each and every photo enlarged in Photos.

You can just drag it to the trash, if you are satisfied that all the files transferred over.

Note that they are *not* duplicate files. They are what are called hard links so that both libraries are sharing the same files. So you won't get quite as much space back as you think.