Claire Dubois

I treat metadata as disclosure rather than trivia, because the fields people find least interesting are the ones that identify. The EXIF block on a camera original holds the make and model, the lens, exposure settings, a timestamp, and on most phones a geotag. A serial number appears on some bodies. None of this is a secret to the camera's owner and all of it is useful to somebody else. Embedded thumbnails are the part people miss. Many images carry a smaller version of themselves inside, so stripping the visible metadata block does not strip the picture if the thumbnail is still there. Structure is worth a paragraph of its own. EXIF is one block inside a broader metadata standard that can also hold captions, keywords, ratings and editing history. Software from different vendors writes different subsets, so a tool that reports no metadata may simply not be reading the format that holds it. Stripping without recompressing is possible for most formats and matters when the image is already compressed once, because a resave costs quality. For a lossless format the round trip is free. For a lossy one, the tool may be able to rewrite the container without touching the image data, and it is worth checking whether it did. Web images get a second consideration. Metadata added by the server on delivery can reintroduce what you stripped, so the fix belongs at upload rather than at export. It is worth checking what a specific tool does before trusting it, since some strip the visible fields and leave the rest, and some re-encode the image to remove everything. Both are sold as the same feature and only one of them preserves the picture exactly.