I do more careful and higher resolution photography in bot gardens with various cameras (and phone too). So I download and edit on computer. And I built up gigantic libraries over the years. Some of them I off load to hot drive and I don't always have them with me .
So for casual stuff like my plants I mostly use the phone, but still I regularly reduce my stash on iCloud by offloading to the laptop: I fill up storage very quick 😁. 200-400 pics in 1 visit is a norm 😎.
So I often do not have an old pic for discussion on icloud, but only on laptop.
So I resize and upload from laptop usually.
But I post from phone often enough (and constantly find and edit new typos..). And then add pics to posts later. But I resize even from the phone by e-mailing a small size to myself.