Blur or pixelate part of a photo online

• Faces of other people - especially children and passers-by who never agreed to be in your post.
• License plates - they can be used to identify the owner of a car.
• Documents - ID and passport numbers, dates of birth, home addresses, bank account and card numbers, barcodes and signatures.
• Screenshots - email addresses, usernames, phone numbers, order numbers, API keys and access tokens.
• The background - house numbers, envelopes with your name, a monitor showing a chat or a spreadsheet.

A light blur keeps the overall structure of the image, and specialised software can sometimes partly reverse it - text is the most vulnerable. For numbers, text and personal data, use a strong setting, coarse pixelation or, safest of all, a black box, which destroys the information completely. For a purely visual effect, such as softening a distracting background, a normal blur is fine.

The effect is baked into the pixels of a brand-new file. Unlike a layer in a photo editor or a shape drawn on a PDF, the original content of the covered area is not hidden underneath - it is replaced, so nobody can “remove” your blur later.

Strength (1-100) is relative to the longer side of the photo, so the preview matches the downloaded file at any resolution. The blur radius equals strength × longer side / 1000 and the pixel block size equals strength × longer side / 1500. For a 4000×3000 px photo:

Rule of thumb: a pixel block should be larger than the height of a single letter or digit you are covering, so no readable shape survives inside a square. For small areas, such as a number on a screenshot, raise the strength or simply use the black box.

• A box that is too small - the edge of a face or the last digit of a number stays visible. Leave a margin of a few pixels.
• Forgotten reflections - a plate visible in a shop window, a mirror or in the background.
• Weak blur on short text - short strings such as a plate number can sometimes be guessed from the blurred outline.
• Sharing the wrong file - make sure you send the downloaded copy, not the original from your gallery.

The downloaded file is rebuilt from pixels, so it contains no camera EXIF data such as GPS coordinates. To strip metadata without touching the picture itself, use the EXIF remover. To find and blur faces automatically, try blur faces.

In the EU and UK, a photo in which a person can be identified counts as personal data under the GDPR, and many countries also protect a person’s right to their own image. Blurring faces, license plates and personal details is a simple way to reduce the risk when you post pictures online, report an incident or share screenshots at work. This is general information, not legal advice.