Optimized storage on iPhone

gossend wrote:

I'm using optimized storage on my iPhone. How do I download a single photo in full resolution?

The easiest way is to download it from https://icloud.com/photos, from the Photos app on your Mac or from iCloud for Windows on a PC.

When you open a photo or video it opens in full resolution.

Download where? You can transfer the same in Full resolution to Mac.

Do not save it on any Clud Drives otehr than iCloud Drive.