After upgrading to the latest 10.10.3, the new Photos app becomes the default app for photo management. When I open the new Photos app, it tells me to choose what photo library, I chose iPhoto library. Then it was importing photos or did something other for a long time to wait. At last, it finished the ready and I can see all my photos in the new Photos app. All things seem good. But when I go to Finder and find there are two libraries (iPhoto library and Photos library) in the Pictures. Photos library is bigger than iPhoto library. In my case, my iPhoto library is 9GB, the Photos library is about 12GB. That means it costs extra 12GB disk space for my photos? This is unreasonable. Have you encountered the same problem? How to get out of this situation? Thanks for any advice.