dahua starlight 5231 onvif snapshot url

System Version 2.622.0000000.18.R, Build Date: 2017-11-10 WEB Version 3.2.1.515090 ONVIF Version 16.12(V2.4.1.510971) I'm trying all sorts of resources, but can't seem to snag a JPEG snapshot from the camera (as I once did, a few years ago.) I suspect it's a combination of stupidity...