The information displayed on “iphone Storage screen” After “Optimism iphone storage” is turned on, is FAKE.
e.g. your iPhone A is 512GB, your local photos take 300GB, total storage used size is 350GB, after icloud synced all photos and optmised iPhone storage, it says 10GB on iPhone used for photos, total storage used is 60GB only. which makes you believe you have 290GB space freed up on your iphone.
Now, if you have another iPhone B with 256GB iphone, you want to restore the iPhone A 60GB data onto this iPhone B, no problem, right?
if you do it through icloud backup, you will notice it downloads full size of photos and videos from icloud, which makes it impossible to restore iPhone A to iPhone B, as the orignal photos liberary size is large than its whole capacity.
if you backup your iPhone A through itunes on local PC, you believe it would be a small back, as it says on iPhone A, the total space used is 60GB. But, NO, you will notice the backup fill size is still the same as before “Optimis iPhone storage”. 350GB ish.
In conclusion, this “Optimis iPhone Storage” won’t let you restore backup from large iphone to small iphone, even it says the storage size is very small, but the number is fake.
And the icloud restore prioritize the photos sycning as its primary task, so you won’t have anything restored before the full res photos take all the space up on small capacity iPhone.
I just experienced the whole thing. Basically Apple is cheating, and lying.
Once you went beyond the storage threshold, e.g. 256GB, 512GB, you’ll have to buy a bigger storage phone. icloud service won’t make you restore a large phone data onto a small phone, even the optimise iphone storage finished and storage information tells you it’s small size used on your phone, but behind it, they are still full resolution photos.