I think lo-res is the best solution to protect your work here, especially if it's high caliber stuff like Francesca's. Another way is to use a high compression jpg or do both. For showing off details one can do cropped closeups of certain elements etc.

It's sad but I think necessary for professionals to protect their work here, or indeed even hobbyist (depending on the work and their approach to it). Working for free shouldn't be a thing, but even worse than that is getting ripped off without knowing it.