EDIT [SOLVED], it’s under “Size”
Still can’t edit subject line to say so.
in previous builds I was able to adjust the scale of a background image but when I bring up the panel and load an image I no longer see a scale.
Expand the region and you will see “Size” at the bottom right.
I’ve always preferred the more physical images as planes addon. Sure they might get in your way (delete them) but at least you don’t have to mess with the N panel.