BHN- wrote: … I know iCloud relies on central storage to make syncing easy
No, I think maybe you misunderstand Photos. You seem to be thinking of "syncing" pictures as transferring files. But pictures aren't files.
I'm thinking of this analogy: These days, lots of people are excited about RAW files from cameras. A RAW file is not a picture, but it contains the information to make lots of different versions of a picture, different exposures, light temperature, ISOs, and so on. From all this, you can decide on the picture that you want. Later, you may choose another version from the same RAW file. Even a jpg is not a picture-- a jpg file holds the information that lets a set of algorithms make a picture. With a jpg, a picture doesn't exist until someone uses an app to create the picture from the included data. But unlike a jpg which makes only one picture, RAW has the information to make lots of pictures. Photos is like RAW on steroids.
Photos is a non-destructive editor. If you edit or crop a picture, maybe cutting off the sides or intensifying the color, the original file is never touched. Instead, your edits are stored in the Photos Database. It's the same for every kind of edit, keyword, comment that you do-- the original picture is not altered, but the information is stored in the Database. So the picture you see on the screen never existed as a file-- it is constructed on the fly from the original plus the information in the database. The edited picture doesn't become a file until you "Export nn Photos." Even then, what you get depends on the parameters you indicate-- always a fraction of all the information that's in the database. When you export a picture from Photos, you have to make lots of decisions, and you get this dialog:
which actually opens up to even more choices. From the database you can export a huge variety of versions of that edited picture, but you can't use any one version to get all the information back. Inside Photos there is also information about faces, objects, text, etc., that won't be included in a jpg file. So a picture file has way less information than what is actually contained in Photos. (The Photos Library also has thumbnail versions of the pictures and preview versions to make scanning through them faster. So there's lots there.)
The point is that iCloud is not just a buffer that holds onto pictures to make transfer "easy." Transfers, like with cable or AirDrop just transfer a file. iCloud synchronizes the entire set of information from its Library with the Library of information that's at the receiving end.
If you want something different, you can let Apple know here:
Feedback - Photos - Apple
