Downloaded Photos from iCloud are Down sized?

why should ANY download have the resolution reduced.

Shared albums have their size adjusted. This is by design as they are hosted on Apple's servers at no financial cost to you. The "cost" of that is a reduced size. Videos are resized as well and limited to 5 minutes.

I use backups to safeguard my original photos.

And that is wise, but using Apple's shared albums as a backup is not.

- Regarding using Windows 10 for iCloud, I have tried it and utilize it daily just as I do on my Apple devices.

- ICloud and its features suit my needs really well in many ways and across platforms which is vital to my work and personal needs. And, one of those features I find to be a huge asset, is the fact that iCloud holds my full resolution photos or what I call "the heavy stuff" so that my devices are free from that weight and storage, yet I have the visual quality I want on my devices.

- Regarding backing up, I am one who quite depends on iCloud to backup my data, and I pay for an upgraded plan to hold, sync, and backup all of it. However, I also backup to external storage drives, iTunes, as well as Google photos & drive which syncs to my gmail accounts I designate & assign for specific purposes. I've gone through a hurricane in which it wiped everything out and I lost everything. So, I learned the hard way to backup daily, using different means and methods. The only salvageable photos were those uploaded to a server.

- With that in mind, I'm very confident in using iCloud's backup feature and know how it functions in correlation to it being a syncing service as well. Regardless, I also know that I could make a random mistake for example and possibly put my iCloud backup at risk or lose data. So, I have backup plans for my backups. Love iCloud's secure server and am reassured my data is safe, but that still doesn't ensure my own human error. Thus, I make sure I have my documents and photos backed up via other means as well.

Bottom line - iCloud definitely holds my full resolution photos, so not sure why yours may not be. At this point, weigh your options, go with what suits your specific needs, and backup in another manner or two to ensure safe keeping.

Hope the above details help a bit & take care ~

Not using Shared Folders - I too pay Apple for the Storage.

I understand that and saw your earlier response,

You suggested that no downloads should be downsized. I pointed out that shared albums do not not contain full size photos.

If iCloud does not contain your full sized photos, there is no explanation. It is designed to.

It appears they may be downsized when sent to iCloud

Your videos and photos stored in iCloud are always full sized.

Manage your iCloud storage - Apple Support

Hi jimshy,

This helped me understand the formatting much better and compression format while maintaining same visual quality:

https://support.apple.com/en-us/HT207022

If you are download the photos from a shared album, as opposed to iCloud Photo Library, you get reduced resolution.

I don't used shared folders either.

I've always had high resolution. Prior to optimizing my photos long ago, I read up first then went for it. No issues since.