Clean

Clean offers auto select or deselect. What is the difference?

If select "deselect" then select "done" and "clean", does it remove duplicate and original?

It occurred to me that my photos are not sitting on my Mac's hard drive. They are taken on my phone and would be located in iCloud. They are viewable on the Mac. Does Apple have a facility for removing duplicates in Photos?

I have just edited a screenshot and I am adding it now. I removed my email address. 

Similars are now down to 1 MB and it is still going.