Not jpeg artifacts. It’s an AI attempt at pixelating real photos (or “Google renders”), per the blog post[1].

1. https://www.justinchavez.com/blog/isometric-sf/

Yep. You can see Google Earth-style photogrammetry artifacts (e.g. around power lines and pylons,) with AI artifacts layered on top, and also the edges of different tiles don't always align so sometimes you get a "double vision" effect.

(I still like it overall)