Two different marks
SynthID is a pixel watermark Google has used on Imagen and Gemini images. It is not an EXIF tag and not a C2PA box. Because this tool does not recompress JPG, PNG, or WebP, it cannot wash SynthID out. No metadata cleaner can. Treat “remove SynthID” as a different job, and not one offered here.
A Gemini download can still have ordinary file metadata, and some Google exports also carry provenance metadata. That part is what the checker can see: C2PA if a content-credential container is in the file, plus XMP, EXIF, and PNG text. Google’s participation in content-credential standards does not mean every Gemini save has a C2PA block. A share-sheet thumbnail often has neither the credential nor a clean SynthID story, because the platform made a new file.
If you need a file with less metadata before an upload, clean it here and read the report. If a platform still labels the upload, the remaining signal may be SynthID or a classifier. Say that plainly to yourself before you re-export ten times.
What to do with a Gemini download
- 1
Save the original download
Use the app’s save or download. A screenshot throws away metadata and also creates a new pixel encoding, which is not a SynthID remover either.
- 2
Separate the two questions
The checker answers only “is there metadata?”. It will not tell you whether SynthID is in the pixels, and it will not give you an AI-probability score.
- 3
Strip the metadata you can see
Run the tool above if the report lists C2PA, XMP, EXIF, or PNG text. The card will say the pixels were unchanged.
- 4
Decide about posting
A cleaned file can still be watermarked. Disclosure rules are unchanged. The disclaimer is the limit.
Do not expect a second pass to erase SynthID
Running the remover twice does nothing extra to the pixels. If the first report was already empty, the file had no metadata left to delete.
Questions
Can this remove SynthID from a Gemini image?
No. SynthID is in the pixel values. This tool leaves JPG, PNG, and WebP pixels as they were.
Does Gemini always write C2PA?
No. Some exports have provenance metadata and some do not. The checker is the test for the file you have.
Will the picture look different after a clean?
Not when the path is lossless, which is the JPG, PNG, and WebP path. SynthID, if it was there, is still there because the pixels did not change.
Is an empty checker proof the image is a photo?
No. It only means this file has no readable metadata of the kinds listed on the checker.