Art researcher Jason Bailey proves the dark web offer of portrait in New Zealand is a fake with a detailed reconstruction of the photo composite:

Popularized by a recent article in Wired magazine, speculation has rapidly spread across the internet about the ad on the dark web for a stolen painting by artist Gottfried Lindauer. Many have suggested the photo of the painting in the ad is photoshopped. I decided to end the speculation and prove it is a composite by tracking down the original photos.

Debunking the Dark Web Sale of the Stolen Lindauer Painting (Artnome)