Where the prompt hides
In a Stable Diffusion PNG the most revealing trail is not C2PA or EXIF: it is the PNG text chunk. A parameters field is usually written there with the positive prompt, the negative prompt and the whole generation setup. It is highly identifying information and it often goes unnoticed when the image is shared.
EXIF and XMP blocks can be added depending on the flow (for example if you pass the image through an editor afterwards).
How to clean it
1. Upload the PNG to the checker: you will see the text-chunk contents, including the prompt. 2. Clean with the available modes (/exif, /xmp) and PNG text-chunk removal. 3. Download the file. It is not recompressed: the pixels are identical (verifiable by hash).
We also support JPEG, WebP, AVIF, TIFF and HEIC if you export to another format.
What cannot be removed
Stable Diffusion is free software and every pipeline is different. Some have the invisible watermark library turned on, which inserts a pixel-level signal. If your image carries it, it is not removed by this tool, because it is not metadata: it is part of the pixels. We remove text chunks, EXIF and XMP; that strips the prompt and the parameters, which is what actually identifies you in most cases.
Privacy
The image is uploaded to our server, processed and deleted after 5 minutes. It is not used for training, we add no watermark, no account is required and the service is free.