Guide · How-to guide · Images
How to anonymise images: document photos, screenshots and metadata
Anonimatum Team
In short
Anonymising an image means permanently covering the text, faces, signatures and number plates that identify someone, and removing EXIF metadata, including GPS location. Pixelating or scribbling on your phone is not always enough.
More and more documents arrive as pictures: a photo of a driving licence attached to an application, a screenshot of a chat submitted as evidence, a photo of a car accident with the registration visible, a TIFF scan from an old archive, or an iPhone HEIC shot of a signed contract. All of them contain personal data — sometimes more than meets the eye.
This guide explains what an image can reveal, why quick edits fail, how to anonymise images step by step, and what Anonimatum does (and does not do) with photos and screenshots.
Step by step
Gather the images and spot the data
Identify visible text, faces, signatures, plates and ID documents, and decide what must remain visible.
Upload the images
Drop the JPG, PNG, WebP, HEIC or TIFF files into Anonimatum; they are converted to PDF and several photos can be grouped into one document.
Enable OCR
Turn on the OCR option so patterns and AI can read the text in the image; pages that receive OCR count double towards your quota.
Choose patterns and AI options
Tick patterns for email or phone, add custom ones for NI numbers or SSNs, and select AI options including the GDPR category for names and plates.
Draw zones over faces, signatures and photos
Cover each face, signature, stamp or ID photo with a zone. Face detection is not automatic.
Preview, apply and download
Run the preview, review marks and zones, apply the anonymisation and download the result.
Check metadata and output
Inspect the image zoomed in, search for the covered text and strip EXIF data from any image you will share.
What personal data an image can contain
- Text inside the image: names, National Insurance numbers, US Social Security numbers, addresses, phone numbers and emails in a screenshot.
- Faces and features: an image of an identifiable person is personal data under the UK GDPR; in US health records, full-face photographs are one of the HIPAA Safe Harbor identifiers.
- Signatures, stamps and ID photos in photographed documents.
- Vehicle registrations, house numbers and shop signs that place a person somewhere.
- EXIF metadata: exact date and time, phone model and often the GPS coordinates of where the photo was taken.
One detail people miss: passports and many ID cards have a machine-readable zone (the lines full of < symbols) that repeats the holder’s name and document number. Covering the name at the top and leaving the MRZ visible anonymises nothing.
Why pixelating or marking up on your phone is not always enough
Phone editors offer pens, highlighters and blur. The highlighter is semi-transparent, so the text reappears when you raise the brightness. Light pixelation or blur over large text can leave it readable or reconstructable, and the original often stays in the gallery or syncs to the cloud. Editing a photo does not necessarily strip EXIF data either: the new version may keep the location.
The safe rule is the same as for PDFs: cover with a solid block, produce a new file without layers or edit history, and then check the metadata.
How Anonimatum handles images
Anonimatum accepts JPG, PNG, WebP and HEIC images (iPhone HEIC photos keep their orientation) and, since version 1.9.0, multi-page TIFF. On upload, images are converted to PDF; several photos dropped together can be grouped into one multi-page PDF, and a TIFF produces one page per TIFF page, with TIFF download available too. If you only need to combine photos into a PDF without anonymising, use the images to PDF tool.
Once converted, the image is handled like a scanned PDF: OCR recognises the text; patterns find emails, phone numbers, bank details or your custom NI number and SSN patterns; AI options detect names, addresses and dates, and the GDPR option also detects licence plates in photographs. Anything that is not text is covered with drawn zones or saved figure patterns.
| Element | Method in Anonimatum |
|---|---|
| Text (name, NI number, address, phone) | OCR + patterns and AI options |
| Vehicle registration | GDPR AI option, reviewed in the preview |
| A person’s face | Manually drawn zone (no automatic detection) |
| Signature, stamp, ID photo | Zone or figure pattern |
| GPS location and EXIF data | Check the output and use metadata removal |
EXIF metadata and GPS location
A phone photo can carry the exact place it was taken, the date and time and the device model. If you share the original file, that information travels with it however well the picture is covered. To strip metadata from an image without changing what it shows, the metadata removal tool accepts JPG, PNG and WebP (not HEIC) and keeps the colour profile. Always do a final check of the properties of the file you are about to send.
Verification and common mistakes
Before sharing an anonymised image
- Zoom in: no face, signature or plate should peek out from the edges of a zone.
- Copy the text of the output PDF and search with Ctrl+F for the covered data.
- Make sure you are not also sending the original or the synced gallery copy.
- Check metadata and the file name (“Licence_Emma_Clarke.jpg” is not neutral).
- For ID photos, cover the back and the machine-readable zone too.
The usual mistakes are trusting the phone highlighter, forgetting faces in the background (passers-by, reflections in windows) and not looking at the whole screenshot: avatars, contact names and phone numbers in the header of a conversation identify someone as well as the message itself.
Frequently asked questions
Does Anonimatum detect faces automatically?
No. The faces option was withdrawn in version 1.9.0. Faces are covered by drawing a zone over each one and checking it in the preview.
In what format do I download an anonymised image?
Images are converted to PDF and the result downloads as a PDF. Multi-page TIFF files can also be downloaded as TIFF.
Does it remove GPS location from my photos?
To strip EXIF and GPS from a JPG, PNG or WebP, use the metadata removal tool. Always check the properties of the file you are about to share.
Is pixelating a face enough?
Light pixelation can leave recognisable features. The safe option is a solid block and a newly generated file.
Anonymise photos and screenshots with confidence
Check the plans and start anonymising images with OCR, patterns, EU-hosted AI and zones for faces and signatures.