Before you clean
Inspect the file first. If it contains Content Credentials, removing metadata may remove or invalidate provenance information. Keep the original as an archival copy.
- Check GPS and serial fields
- Note EXIF orientation
- Check for an ICC color profile
- Check for C2PA before modifying the copy
Lossless metadata removal
A segment-level JPEG cleaner can preserve entropy-coded image data. PNG and WebP cleaners can remove metadata chunks while leaving image chunks and animation frames untouched. This is different from opening and re-exporting the pixels through a canvas.
Verify the output
Parse the cleaned copy again, confirm the targeted fields are gone, verify that it still decodes, and compare the file size. A tool should only claim pixel preservation for code paths it actually checks.
Choose cleaning rather than conversion when pixels matter
A metadata-only cleaner edits the container around the encoded image. A converter decodes the picture and creates a new encoding, which can alter pixel values and compression artifacts. Both can reduce ordinary metadata, but they are not equivalent operations.
Use cleaning when the current format and dimensions are already suitable. Use conversion when you need a smaller size, a different format or resized dimensions, and retain the original if image fidelity or evidence preservation matters.
- Cleaning targets container blocks
- Conversion creates new encoded pixels
- Neither redacts visible details
- Both outputs should be reparsed
How the preservation test was judged
The test did not compare only file size, because a smaller output could still be corrupted or re-encoded. It located the JPEG scan, PNG IDAT and WebP VP8 or VP8L regions, ran the cleaner, and confirmed the relevant image payload remained byte-for-byte present on supported fixtures.
Container-level preservation does not guarantee that every viewer will display every unusual file identically. Orientation, ICC profiles, animation flags and C2PA structures need explicit handling, and malformed inputs should be rejected rather than repaired silently.
Verify the copy before deleting anything
Open the result, confirm its dimensions, and analyze it again for GPS, owner, serial, XMP and text fields. If the tool reports a limitation, keep the original and do not substitute the cleaned file in an archive.
Never overwrite the only copy during a privacy workflow. A separate “-clean” file makes it obvious which asset is intended for sharing and preserves the evidentiary or photographic value of the original.
What this does not prove
A metadata result describes the fields and structures that the supported parser could read. It does not, by itself, prove authenticity, intent, authorship or the truth of the visible scene.