Counts cover descriptive and personal fields. File properties and technical colour/codec data are listed separately. A completed scan covers the listed families; it cannot rule out every possible hidden field.
JPEG
Inspected: EXIF/GPS, IPTC, XMP and JPEG comments
Removable: EXIF (except orientation), IPTC, XMP and comments
Format, quality and features: Encoded pixels, orientation and ICC profiles retained; embedded EXIF/Photoshop thumbnails removed.
Limits: Maker notes and unknown application segments cannot be interpreted. XMP-only/conflicting orientation and non-sRGB EXIF colour without ICC block cleaning. ICC profiles may contain descriptive fields and are retained for colour.
PNG
Inspected: Text (tEXt/zTXt/iTXt), EXIF/GPS, XMP and modification time
Removable: Text, EXIF (except orientation), XMP and modification time
Format, quality and features: Encoded pixels, dimensions, transparency and colour chunks retained. Animated PNG cleaning is disabled.
Limits: Unknown ancillary chunks and private EXIF tags cannot be interpreted. XMP-only/conflicting orientation and non-sRGB EXIF colour without ICC block cleaning. Colour profiles are retained for appearance.
WebP
Inspected: EXIF/GPS and XMP
Removable: EXIF (except orientation) and XMP
Format, quality and features: Encoded pixels, orientation, dimensions, transparency and ICC profiles retained. Animated WebP cleaning is disabled.
Limits: Unknown RIFF chunks and private EXIF tags cannot be interpreted. XMP-only/conflicting orientation and non-sRGB EXIF colour without ICC block cleaning. ICC profiles are retained for colour.
PDF
Inspected: Document Info (including custom keys) and referenced document/page/object XMP streams
Removable: Descriptive document Info and Metadata streams
Format, quality and features: Rewrites the existing document; preserves pages, forms, links and bookmarks. Attachments, signatures and encrypted PDFs block cleaning.
Limits: The technical Trapped printing flag is retained. Annotation contents, form values, hidden text, embedded assets and arbitrary private objects are outside metadata coverage. Unsupported document features and indirect Info values block cleaning.
MP3
Inspected: ID3v1/v2, APE tags and native fields including comments/artwork
Removable: ID3/APE tags and artwork
Format, quality and features: Tag containers stripped directly; encoded frames and gapless playback headers retained.
Limits: Private binary payloads are uninspected; parser warnings block cleaning. Free-format MP3 and unknown trailing data block cleaning. Codec headers remain.
M4A
Inspected: MP4/iTunes common and native tags; container dates
Removable: MP4/iTunes descriptive tags and artwork; container dates reset
Format, quality and features: Audio stream copied to M4A without re-encoding; container structure changes.
Limits: Only a single AAC or ALAC audio stream is eligible. Chapters, video, encryption and unknown container boxes block cleaning. Technical brands and empty date headers remain.
WAV
Inspected: RIFF INFO, ID3 and fixed Broadcast Wave header tags
Removable: RIFF INFO and ID3 descriptive chunks
Format, quality and features: Audio stream copied to WAV without re-encoding; container structure changes.
Limits: Only a single PCM stream is eligible. Broadcast Wave extensions, WAV XML and unknown RIFF chunks produce partial scans and block cleaning. Technical fmt/data headers remain.
FLAC
Inspected: Vorbis comments, pictures and native fields
Removable: Vorbis descriptive comments, pictures and application blocks
Format, quality and features: FLAC stream copied without re-encoding; container structure changes.
Limits: Codec stream information and technical vendor strings remain. Unknown metadata blocks block cleaning.
OGG
Inspected: Vorbis/Opus comments, pictures and native fields
Removable: Vorbis/Opus descriptive comments and pictures
Format, quality and features: Single Vorbis/Opus audio stream copied to OGG without re-encoding; pages/checksums change.
Limits: Chained/multiplexed OGG streams block cleaning. Required codec/vendor headers remain.
100 MiB maximum per file. Originals stay unchanged. Removing metadata does not redact visible text, pictures, form values or audio content.
