Testing AI image watermarks: C2PA and SynthID

The author tested C2PA and SynthID on AI-generated images, finding that C2PA metadata is easily stripped with ImageMagick while SynthID survives metadata removal, cropping, and JPEG compression. SynthID was not detected in a simple rectangle image, and analysis of a plain white AI image showed lower spectral entropy and near-zero spectrum correlation versus histogram-matched random controls. Attempts to suppress high-energy FFT coefficients did not isolate the watermark, though the plain white image showed clear spectral structure.