why can't I upload photos to icloud from my old 2013 macbook?

Trying to back up my old iphoto library (on 2013 macbook) to icloud so I can bring it in to Photos on another machine (2019 Imac). I've plenty of storage because i just upgraded, but now there doesn't seem to be a photo option when i go into icloud. There is an icloud option on IPhoto, but it seems limited to the last 31 days, so of no use to create an online backup or transfer an entire library.

Any advice?