Does iCloud Photos - Optimize Mac Storage grow disk usage based on disk size? If so, how much does it typically use?

[EugW]

Hi. I have a secondary machine in which I installed a 500 GB SSD. The machine has very little on it, but I've seen its disk usage grow from just about 50 GB to 225 GB usage.

After looking around a bit I see that it's because my Photos library is around 185 GB now. My Photos library is a little over 500 GB. Photos is set to download all originals to my main machine, but not on this secondary machine where it's set to "Optimize Mac Storage". I'm a little surprised that this option would allocate nearly 2/5th of my entire SSD space to Photos. Is this par for the course?

If I start to fill up the drive with other stuff, will it reduce Photos storage space usage? Also, is it possible to force macOS to reduce this usage of storage space? I was only planning on using this machine for a few months and then repurposing it for the family, but while leaving my existing account on there as the main admin account. I wasn't expecting this admin account to take up half the drive though.

 

[99 others]

I have the same question. I have 1TB of photos and my SSD is just 1TB. What happens when I sync my photos with Optimize Mac Storage? I only want to see previews and download the originals if necessary.

 

[Darmok N Jalad]

From what I gather, Optimize storage tells your Mac to download scaled down images of your entire library, where, ideally, viewing them at your display's native resolution is seamless. It's when you zoom in on an image that it has to download the full-size image. I believe the OS looks at your available storage, and if you have enough free space, it will create these preview images for your entire library, if they all fit. It might also go back a certain period of time from the current date and have the full-sized images downloaded, since those are the most recent and most likely to be manipulated or shared. It's not a one-size-fits-all scheme, but rather it will flex based on how you use the rest of your storage. If you start filling the disc, it will scale back all of the above to reduce its total footprint.