If you open i Photo or Aperture after you upgrade to Photos, you’ll be asked if you want to open your library there or in Photos.Any changes or edits you make in i Photo or Aperture aren't reflected in Photos.If you’d like to migrate a library from i Photo 7 or earlier, use Apple’s free i Photo Library Upgrader tool to prepare your library first.If you store your Photos library in a location that's part of a cloud service (for example, Dropbox, Box, or Google Drive), your library might be damaged by the syncing process. To see your photos on all your devices, you can use i Cloud Photo Library. i Photo — and Aperture, if you downloaded it — remains on your system in the Applications folder, and you can continue to use it.For a full list of what items can and can't be copied (which varies depending on what version of i Photo you're using), look here.To begin a merge, click the "Merge Libraries" toolbar button, or select "Merge Libraries" from the Library menu.I have my first i Photo library on my vintage Mac Mini. You can copy all files to the new i Mac first, or access them directly from the individual machines.
Do this for a different library, and you will now have two Photos windows on your screen with different libraries open.In many cases, if you had a single i Photo library in your Pictures folder, your entire library — including your photos, videos, projects, albums, and so on — automatically appears in Photos the first time you open it.If you have more than one photo library on your Mac, then Photos will ask which one you want to upgrade the first time you open it.When importing pictures, Aperture can copy images into its library, thus creating duplicates of each picture, or it can reference, or point to, the existing files in your i Photo Library folder.Although you’ll save disk space by referencing your i Photo files, you’ll lose out on a key advantage of using Aperture: its Vault feature won’t back up referenced files (see “Why Move to Aperture? If you’d like to try out Aperture but aren’t ready to import your images into the program, consider using referenced files as a trial run.