GeoTag Photos metadata retention test kit 1.0

Test ID: GTP-META-2026-001
Published: 2026-07-17
License: CC BY 4.0

Purpose
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This kit measures whether an image platform returns the original file, re-encodes
the image while retaining metadata, keeps only some fields, or removes the tested
metadata entirely.

The controlled-pipeline folder also shows why the upload surface matters. It includes
a byte-preserving copy, default re-encodes, and equivalent re-encodes that explicitly
retain metadata. Results are recorded in controlled-pipeline-results.json.

Verified platform observations are recorded in platform-results.json and
platform-results.csv. Public records are anonymized and exclude account names,
handles, post URLs, media URLs, platform identifiers and account screenshots.

The coordinate is synthetic and the image is a test card. Do not use this file as
location evidence.

Test procedure
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1. Choose one source file and confirm its SHA-256 value in manifest.json.
2. Upload it through one precisely named platform surface.
3. Retrieve the platform-delivered file. Record how it was retrieved.
4. Calculate the returned file's SHA-256 value.
5. Inspect GPS, DateTimeOriginal, ImageDescription, Artist, Copyright and XMP keywords.
6. Add the result to platform-results-template.csv.

Classification
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byte-identical: SHA-256 matches the source file.
retained: the file changed, but every tested metadata field remains readable.
partial: at least one tested field remains and at least one is missing or changed.
stripped: none of the tested fields remains in the delivered file.
not downloadable: the platform offers no supported way to retrieve a comparable file.

Scope warning
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A delivered copy does not reveal everything a platform stores internally. The result
applies only to the tested upload surface, retrieval method, file format, app version
and test date.