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About this tool
Write a sidecar file recording corrected dates and GPS coordinates for photos you own, without changing the originals.
The EXIF Timestamp & Geotag Editor records the date and coordinate changes you want made to a photo as a JSON sidecar file, saved alongside the original as filename.altftool-sidecar.json. It deliberately does not rewrite the image's own EXIF block: browsers cannot safely repack every maker-note and sub-directory structure a camera writes, so instead of corrupting the file it produces an explicit, machine-readable record of the intended edits. Each sidecar carries four fields — the source filename, the edits you typed, an ISO 8601 generation timestamp, and a warning that the original bytes are untouched.
Open EXIF Timestamp & Geotag Editor on AltFTool — it loads instantly in your browser.
Choose the photo under 'Local file(s)' — only the first file you select is processed.
Type the corrected date in EXIF's YYYY:MM:DD HH:MM:SS form and signed decimal coordinates into 'Characters, metadata edits, or processing notes', then press 'Run local workbench'.
The browser downloads yourphoto.jpg.altftool-sidecar.json holding source, requestedEdits, generatedAt and a warning that the original bytes are unchanged.
Nothing is re-encoded or repacked, so checksums, maker notes and RAW-adjacent structures survive exactly as the camera wrote them.
The sidecar timestamps itself in ISO 8601 and names the source file, so the intended edit is reviewable and reversible rather than baked in.
The output states in plain text that the image bytes were not modified, instead of implying an EXIF rewrite that did not happen.
No — it writes a separate JSON sidecar and leaves the original file untouched, which the sidecar itself states in its warning field. To apply the change to the image you need a dedicated EXIF writer such as ExifTool, using the sidecar as your instruction list.
Four keys: source (the original filename), requestedEdits (the text you entered), generatedAt (an ISO 8601 timestamp of when it was produced), and warning. It downloads as your-photo.jpg.altftool-sidecar.json so it sorts next to the image.
One file per run — the tool reads the first file you provide and produces one sidecar for it. For a large batch, generate the sidecars you need individually or script the same JSON shape yourself, since the format is only four plain fields.
Use unambiguous formats you can feed to a writer later: dates as YYYY:MM:DD HH:MM:SS, which is EXIF's own DateTimeOriginal format, and coordinates as signed decimal degrees such as 48.8584, 2.2945. The field is free text, so the tool stores whatever you type verbatim.