I'm currently running the 10.10.3 public beta on my MacBook Air and I decided to switch over to iCloud Photo Library. All of the photos from my iPhone/iPad and my iPhoto Library transferred over with no hassle. Some photos show up twice. Since I have my iPhone/iPad set to "optimize device storage" and my Mac set to "download and keep originals," I'm guessing one is the full-resolution shot, and one is the compressed image. If anyone could tell me how or why some images are showing up twice in iCloud Photo Library, I'd appreciate it. Thanks.