iCloud syncing to Photos issue

Hi everyone,

I have a friend that has set up iCloud through her iPhone, and now that she's linking said iCloud account to her iMac, she has said that not all iCloud photos are shown in Photos.

I pointed her to the Preferences > iCloud section of Photos and told her to make sure iCloud Photo Library was selected and either "Download Original to this Mac" or "Optimize Mac Storage" and she says that she has selected the former, and that the issue remains.

-Is it possible that the downloading takes significant amounts of time?
-What might be the issue here?

Thanks!

via ehMac.ca http://ift.tt/2gy3g70