iCloud Photo Library - when do they download

[dgsgc]

Hi all,
I’m running out of space on my MacBook Pro to store all originals of my iCloud Photo Library.

I’m planning to buy an iMac which I hope to set up to download originals on and then change my MacBook Pro to optimise storage.

Do I need to open the photos app on the iMac in order for new photos to be downloaded in original size or does it happen in the background?

Thanks

 

[NazgulRR]

Happens in the background for me.

 

[dgsgc]

OK great so my plan will work.

Optimise macbook pro
Add new photos to MacBook pro
Macbook pro uploads to iCloud
iMac stays in a utility room and is never used
Full size originals will download to iMac without me running the photos app

?

 

[NazgulRR]

Yup. I do it very similarly with a mac mini used as a headless server.

 

[dgsgc]

Thanks a lot