It turns out that Facebook does not allow external plugins to display posts from a personal Facebook tiimeline. Only posts from a Facebook page or group can be selected and displayed remotely. This is apparently for privacy reasons.
I picked up a Custom Facebopok Feed plugin from Smashballoon to display selected Facebook posts on my WordPress blog. Its FAQ mentions this restriction.
So I may have to make a proper SRD Books Facebook page, and post art things to that. Since many of these would be various stages of artwork and book preparation, that makes sense. But general sketchbook posts like I’ve been doing lately? I’ll have to think about it. Maybe I can sort and redisplay them on my personal page and then link to that.
A proper FB, Twitter, Instagram, Pinterest, etc page for SRD Books is something that Orzala would probably recommend anyways…