[Butterbeer]

I’ve had a Mac for years but have only just started using Photos a couple of weeks ago and haven’t uploaded to Facebook from it yet. However, I just had a super quick experiment and if you open Facebook in Safari (or whatever browser you use) you can click on the photo in Photos and drag the photo down to Safari/whatever browser icon, then to the open Facebook window and drop it in the Create Post bit. I feel like there will probably be other ways but that’s all I’ve worked out so far! I’ll keep experiments as I’ll need to know this soon too!