How to prevent duplicate image downloads from iCloud shared album to iPhone Library?

opa_bear wrote: Downloads of pictures from shared album to iPhone Library generates duplicate images,

Can you tell us what you mean by "duplicate images?" The pictures in a shared album are typically lower resolution than those in the Library, so they aren't duplicates.

This picture

in my Library is 7399x4162 pixels. But in the Shared Album that picture is only 2731x1536. The Original file in the Library is 19.9MB, but the picture in the Shard Album is 0.82MB, way, way smaller. So the shared album picture is not only fewer pixels, but it is more highly compressed, having less detail. Photos doesn't see these as duplicates, and they don't show in the Duplicates folder.

The Shared Album versions don't take up any actual space in your Library, and their size doesn't count against your iCloud subscription at all. So which picture are you throwing away?

opa_bear wrote: …second image was identical to the first but had a different file number (ex: 2245.jpg) but both were the same reduced file size/dimensions.

I'm guessing that you mean IMG_2245.jpg, is that right? Or does it have another form? When a phone creates its own image, it uses a file name that is in line with the pictures taken by the phone. Does this filename look like it's in line with your recent photographs?

I'm not sure I got this: are you the "owner" of this Shared Library, or are you receiving this Shared Library from someone else?