# AI Image Detectors

Detectors read statistical residue, not subject matter. These pages describe what each one measures and what naturalization changes.

- [What Sightengine measures when it scores an image](https://passreal.com/detectors/sightengine): Sightengine returns a probability, not a verdict, and it runs as an API inside moderation pipelines. Here is what it measures and where thresholds sit.
- [What error level analysis shows, and what people think it shows](https://passreal.com/detectors/fotoforensics-ela): FotoForensics runs ELA, which shows JPEG recompression differences, not AI generation. Here is what the colours mean and why the tool gets misread daily.