how to get photos off of icloud to my imac

I caqnnot seem to figure this out, I am out of storage space, I do not want to pay for more and I just want to quit using the cloud for photos and keep them on my imac (and maybe google photos), but how!?!?
I need an easy way, if there is one please

 

Thank you but I guess I should have been clearer.

I know how to download one photo at a time, or a bunch, by selecting each one, but how to get them all off, or all selected at the same time, so that I do not have to select individually all 1758 photos.

I could just take them from my phone and ipad, but they are optimized there. I want the full size photos gone from the icloud so I can quite using it altogether for photos.

 

thanks, I already tried that too. It tells me I am out of space to upload when I am trying to download them.