Unlike with the printers, there is probably no database of the CMOS sensor irregularities of all cameras ever made. But if you upload pictures under your government name and the take pictures with the same camera and share them anonymously, this could be traced back to you in theory.
The Harry Potter thing was EXIF https://www.eff.org/deeplinks/2007/07/harry-potter-and-digital-fingerprints
But pictures can also be traced back to a camera based on irregularities in the camera sensor https://www.scientificamerican.com/article/tracing-photos-back-to-the-camera-that-snapped-them/
Unlike with the printers, there is probably no database of the CMOS sensor irregularities of all cameras ever made. But if you upload pictures under your government name and the take pictures with the same camera and share them anonymously, this could be traced back to you in theory.