Can I delete I-photos library after installation of Photos?

When you open an iPhoto Library in Photos it creates a new library. The image files in the new library are created in a very smart way. Photos created the new files as hard links. A hard linked file is stored in the same place as the original file, so the new file does not need extra storage. But the operating system remembers how many files are stored there, and only if the last linked file has been deleted the storage will be freed. You can delete both files independently, and the other linked file will continue to work.

So you can delete the iPhoto Library if you do not need it any longer, but it will not save much storage:

See these documents:

• Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support
• Six Colors: The (hard) link between Photos and iPhoto

But delete your iPhoto library only after you are sure, that yu do not need it any longer, after checking if all photos migrated safely. I#d keep a backup of the library somewhere.

If you enter Time Machine and go back in time along the timeline at the right border of the display, you can check the size of the libraries.

• Select the Photos Library in the Finder, then launch Time Machine.
• As you click different times in the timeline you will see the reported size of the library change.

Do you mean that it still will occupy about 185 GB if I delete Iphoto library?

Only, if your libraries are still using hard links. If all photos in your Photos Library have been imported independently and not by letting Photos migrate the iPhoto Library, the storage occupied by the iPhoto Library should be released, once you delete it and empty the Trash.

The Terminal.

You would have to compare the inodes (the entries in the file table) of the original master files.

But the screenshot in your original post strongly suggests that the two libraries are sharing the storage and are not actually using twice the storage - only 72GB for "Bilder". Each library has files of the size ~ 85 GB, but because identical image files in both libraries are using the same disk blocks, the total in file size is much less for the images.

Only the Finder is counting them twice, because the Finder does not know if a files are hard linked. For all practical purposed they look and behave like ordinary files.

If two files are hard linked, the inode numbers will be identical, when you list the file with the ls -li command in the Terminal:

For example, looking into the packages of an new migrated Photos library and the original iPhoto Library. Everything looks duplicated with the same size:

The Terminal is showing this, when I type "ls -li " into the Terminal and drag one of the master files behind this command:

Hermione:~ dreschle$ ls -li /Users/dreschle/Pictures/Photos\ Library\ 2.photoslibrary/Masters/2015/05/28/20150528-184932/IMG_0966.JPG

39167952 -rw-r--r--@ 3 dreschle staff 1283723 25 Mai 12:00 /Users/dreschle/Pictures/Photos Library 2.photoslibrary/Masters/2015/05/28/20150528-184932/IMG_0966.JPG

Hermione:~ dreschle$ ls -li /Users/dreschle/Pictures/iPhoto\ Library.migratedphotolibrary/Masters/2015/05/28/20150528-184932/IMG_0966.JPG

39167952 -rw-r--r--@ 3 dreschle staff 1283723 25 Mai 12:00 /Users/dreschle/Pictures/iPhoto Library.migratedphotolibrary/Masters/2015/05/28/20150528-184932/IMG_0966.JPG

In both libraries are the files listed with the identical inode number 39167952 (shown in red in my screenshot) , meaning they are linking to the same physical file in the file table. For the Finder both files are separate, regular files and so it is reporting the size twice.

When I compared the used space on my hard drive right after migrating the test library with 40 photos, the used storage had not been increased much:

Re: Can I delete my old iPhoto library after migrating data to iphoto in iCloud?

Delete the iPhoto library anyway, if you do not need it any longer. It will free some storage. But you need to free storage urgently, if you only have a bit more than 5GB free. That is not safe.

Is something still ongoing since the implementation of Photos library?

That is hard to say for me, since I do not know, how you are using Photos.

Did you perhaps enable iCloud Photo Library and optimize Storage? did you sync the library with iTunes, so the iTunes Photo cache changed?

Your Photos Preferences are the same my settings. You don't use the optimize storage option, so there is no reason why the used storage should decrease. Photos will emtpy the trash outomatically after a month, perhaps have photos been removed.

For your Apple TV ask in the forum for Apple TV, I do not use it.

Syncing with iCloud disables iTunes Photo Sync, so the iPod Photo Cache maxy have been removed.It can be quite large. iTunes: Understanding the iPod Photo Cache folder