Yes, I have a program which plots vector fields [1], part of CI creates some plots for cases which have previously caused issues [2]. They are not meant to be attractive, rather to exercise those edge cases. Example output here: [3]
If you would be willing to automate that, why not using the existing vis reg tools? Is there something custom that you have in the setup that prevents you from going with the cloud or OSS solution?
There're lots of way that things could go wrong here, things that I could see visually immediately, but enumerate and identify all those cases with some visual recognition code? I'll keep it as a 10s glance every now and again ...