How can I make my "photo library" to "system photo library"?

[kevinsjfl3jlj]

Hi, I wanted to clean install my Mac before. So I copied my "photo library" to external drive.
And after installing new os, I just pasted the "photo library" to the same location.
However it looks like that I can't use iCloud because it is not system photo library.

Can you let me know how can I make my "photo library" to system photo library?

Thanks.
[doublepost=1525556186][/doublepost]I googled and found it.
Thanks.