Exchangeable Image File Format (EXIF) Viewer & Editor

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Photo metadata, often called EXIF, are descriptive tags saved inside an image that record the camera, lens, capture settings, date, and sometimes location. Many people use a photo metadata viewer and editor to check what was recorded and decide what to keep before sharing.

You load a picture and the tags are read so you can review camera details and see a map if coordinates exist. Then you choose whether to keep essential information, edit selected fields such as the date or artist, or remove everything for a clean copy.

Results come back as a new image in JPEG, PNG, or WebP with your chosen quality, and rotation is applied so pixels are upright when the file is saved. A compact summary shows dimensions, file size, and the count of tags detected so before and after checks are straightforward.

For example, a vacation photo may include the camera model, exposure, and a precise location. You can clear the coordinates and export again so the shared copy keeps the date and camera notes but no location.

Be mindful that valid looking tags do not prove a device or account, and some maker specific notes may exist in originals that you decide not to publish. Consistent inputs and a quick scan of unusual values improve results.

Technical Details:

Exchangeable image file metadata describe how a photo was captured and where, including camera make and model, lens model, exposure time, aperture, ISO sensitivity, focal length, orientation, capture timestamp, and Global Positioning System coordinates when available. The readout here is a snapshot of those quantities for a single file with optional user edits applied.

Computed displays convert raw fields into human friendly forms. Exposure time is shown as a whole second or as a reciprocal, aperture as an f‑number, focal length in millimetres, and latitude and longitude in decimal degrees for viewing while the saved EXIF stores them as degrees–minutes–seconds rationals. Orientation codes are normalized so exported pixels are upright.

Results fall into three handling choices: keep a curated set of tags, apply your edits to that curated set, or strip all metadata. Only JPEG exports embed metadata; PNG and WebP exports omit metadata regardless of selection. Comparisons are valid within the same image and export settings; cross device comparisons should account for missing or nonstandard tags.

Accept an image file and read metadata locally.
Derive display values for exposure, aperture, ISO, and focal length.
Detect GPS and show a map when coordinates exist.
On export, draw the image to a canvas, applying auto‑rotation if selected.
For JPEG and metadata “keep” or “edit”, write a curated EXIF set; otherwise save without metadata.

Symbols and units referenced in the display and export
Symbol	Meaning	Unit/Datatype	Source
t	Exposure time	seconds	Metadata
N	Aperture (f‑number)	unitless	Metadata
ISO	Sensitivity rating	unitless	Metadata
f	Focal length	mm	Metadata
φ	Latitude	degrees	Metadata / Edit
λ	Longitude	degrees	Metadata / Edit
h	Altitude	m	Metadata / Edit
θ	Orientation code	integer	Metadata

\begin{array}{lcl} d & = & floor (| x |) \\ m & = & floor ((| x | - d) \times 60) \\ s & = & ((| x | - d) \times 60 - m) \times 60 \end{array}

Worked example of GPS encoding
Worked Example	Input	Saved EXIF
Latitude	φ = 37.774900°	Ref = N; [ [37,1], [46,1], [2964,100] ]
Longitude	λ = −122.419400°	Ref = W; [ [122,1], [25,1], [984,100] ]
Altitude	h = 15 m	Ref = 0; [1500,100]
Orientation	θ = 1	Orientation saved as 1 (upright)
Exposure	t = 0.008	Display “1/125 s”
Aperture	N = 2.8	Display “f/2.8”
Focal length	f = 50	Display “50 mm”

Export parameters and their effects
Parameter	Meaning	Unit/Datatype	Typical Range	Sensitivity	Notes
Format	Output image type	MIME	JPEG \| PNG \| WebP \| Auto	High	“Auto” keeps the source type when possible.
Quality	Lossy encoding quality	percent	10–100	Medium	Ignored by PNG; applies to JPEG and WebP.
Auto‑rotate	Applies Orientation so pixels are upright	boolean	on \| off	Low	Exported EXIF stores Orientation as 1.
Metadata mode	Keep curated tags, apply edits, or strip	enum	keep \| edit \| strip	High	Only JPEG embeds metadata on export.

Validation and bounds enforced by the interface
Field	Type	Min	Max	Step/Pattern	Error Text / Behavior
Source file	file (image/*)	—	—	accept=image/*	“Unsupported file type. Please choose an image.”
Quality	range	10	100	1	PNG ignores Quality.
GPS latitude	number	−90	90	0.000001	Edits outside range are clamped.
GPS longitude	number	−180	180	0.000001	Edits outside range are clamped.
GPS altitude	number	—	—	0.1	Saved as a rational number in metres.
Date taken (edit)	datetime‑local	—	—	YYYY‑MM‑DDTHH:MM	Invalid values are rejected on save.
Metadata writing	toggle	—	—	JPEG only	Other formats disable “keep” and “edit”.

Units, precision, and rounding. Exposure shows as seconds to three decimals when t ≥ 1; otherwise as 1/round(1/t). Aperture shows to one decimal, focal length to the nearest millimetre, and latitude/longitude display to six decimals. File size displays in kilobytes with two decimals. EXIF timestamps are saved as “YYYY:MM:DD HH:MM:SS” without a timezone.

I/O formats.

Accepted inputs and produced outputs
Input	Accepted Families	Output	Encoding/Precision	Rounding
Image file	Any type beginning with image/	JPEG \| PNG \| WebP	JPEG quality 10–100; PNG lossless; WebP quality 10–100	As above
Metadata	EXIF fields where present	Curated EXIF subset (JPEG only)	GPS saved as D/M/S rationals	Seconds ×100 denominator

Networking & storage behavior. Image parsing and export are browser‑based and use temporary object URLs; no image is sent to a server. When viewing the map, tiles are requested from a public tile service. Clipboard and downloads are performed locally.

Security considerations. Removing or editing metadata reduces accidental disclosure of device and location details. Because only a curated subset is written on export, maker notes and device serials are not propagated. Always review the Info tab before sharing.

Assumptions & limitations.

Only JPEG embeds metadata on export; PNG and WebP omit it.
Heads‑up “Keep original” writes a curated subset, not a full pass‑through.
Orientation is normalized to 1 in exported EXIF.
Map requires network access for tiles.
Undefined or missing fields display as blank.
Edits are limited to common descriptive fields and GPS.
Heads‑up Advanced switches shown for GPS scrubbing, rounding, digitized date, and serial scrubbing are not applied by the current build.
Capture time saves without a timezone per EXIF conventions.

Edge cases & error sources.

Non‑image files are rejected with a clear message.
Unreadable images trigger “Could not load image.”
Metadata library not ready yields “EXIF library failed to load.”
Corrupt EXIF produces “Failed to read EXIF metadata.”
Export failures show “Export failed.”
Very large images may be limited by device memory.
GPS edits outside limits are clamped to valid ranges.
Dates that do not parse are not accepted for saving.
PNG ignores the Quality setting by design.
Map remains blank when no coordinates exist or network is unavailable.

Privacy & compliance. Files are processed locally; nothing is uploaded. Map tiles are fetched from a third‑party service when the map is viewed.

Step‑by‑Step Guide:

The photo metadata workflow reads a file, lets you adjust selected tags, and saves a shareable copy.

Drop a photo or choose one from your device.
Open Info to review tags; click the edit icon to adjust a field.
Switch to Map to confirm coordinates when present.
Pick Metadata mode: keep, edit, or strip.
Select Format and adjust Quality if JPEG or WebP.
Use Export to preview and download the new image.

Example: to remove location but keep the date, choose “edit”, clear GPS fields, leave the date as is, then export as JPEG.

Copy a quick report with “Copy CSV” or save the JSON payload for records.
Set Auto‑rotate on if the original appears sideways.

You now have a clean copy tailored for sharing.

FAQ:

Is my data stored?

Processing happens locally; images are not sent to a server. If you open the map, only map tiles are requested from a public service.

Files are processed locally; nothing is uploaded.

How accurate are the camera settings?

They reflect what the file records. Some cameras omit fields or use nonstandard tags, so missing or blank values are normal.

Which formats can I export?

JPEG, PNG, and WebP. Only JPEG embeds metadata on export; PNG and WebP omit it. Quality affects JPEG and WebP; PNG is lossless.

How do I remove location data?

Choose “strip” to remove all tags or “edit” and clear GPS latitude, longitude, and altitude, then export.

Why is the map empty?

The file may not contain coordinates, or network access to map tiles is unavailable. The Info tab will still show other tags.

Why do some advanced switches not change output?

In this build those switches are shown for clarity but are not applied when writing metadata. Review the Info tab to confirm saved fields.

Can I keep the date but remove other tags?

Yes. Use “edit”, keep the Date Taken value, clear the fields you do not want, and export as JPEG.

What does an undefined value mean?

It usually means the field was not present in the file. You can add a value in edit mode for common fields.

Troubleshooting:

“Unsupported file type” → choose a file whose type begins with image/.
“Could not load image.” → the file may be corrupt; try another copy.
“EXIF library failed to load.” → reload the page and try again.
“Failed to read EXIF metadata.” → continue without tags or pick another file.
“Export failed.” → reduce image size and retry.
Map not showing → ensure GPS exists or connect to a network.
Edits not saving → ensure values are within allowed ranges.

Exported JPEG lacks edits: switch Metadata mode to “edit”, then re‑export.

Glossary:

EXIF: A standard set of tags describing how and when a photo was captured.
Orientation: A code that tells viewers how to rotate the image for upright display.
F‑number: Aperture size expressed as f/N; lower values admit more light.
Exposure time: Shutter duration measured in seconds.
GPS IFD: The group of EXIF entries that store latitude, longitude, and altitude.
Object URL: A temporary local URL used to preview and download generated files.