How to blur faces, plates and screens out of a photo, without uploading it

Open the photo in VEIL. Press Find and blur faces and it looks for faces itself, using a small detection model that runs in the tab; drag a box over anything it missed, or over a plate, a badge, a screen or a street sign. Each box is pixelated into the picture at its full resolution, and the file you save is a fresh PNG with the pixels changed for good. The photograph is never uploaded, and once the page has loaded it works with the network off.

Pixelation, not blur

These are not the same operation and the difference has consequences.

A Gaussian blur averages each pixel with its neighbours. It is a smooth, reversible-looking transformation, and in some conditions it is genuinely reversible: with a known blur radius, a known face and enough compute, deblurring is a solved problem, and there have been real cases of blurred faces and blurred text being recovered. A light blur over a number plate is decoration.

Pixelation replaces each block with one average colour. Information inside the block is not attenuated, it is gone. There is nothing left to undo, provided the blocks are large enough. That is why VEIL pixelates rather than blurs, whatever the button says, and why the block size is scaled to the box rather than fixed.

One caveat that applies to both, honestly: if somebody has the original photograph, no amount of anything on the copy helps. This protects the copy you publish.

What to cover, beyond the obvious

Faces are what people remember to do. The things that identify somebody in a photograph and get forgotten:

• Number plates, including reflections of them in windows and paintwork.
• Screens. A laptop or phone in shot, legible or not: a modern camera resolves more than your eye did at the time.
• Lanyards, badges and name tags, and the printed rota on the wall behind everybody.
• House numbers, street signs and shop fronts, which place the photograph precisely.
• Tattoos, distinctive clothing and mobility aids, which identify people in a small community as reliably as a face.
• Children's school uniforms. A crest is an address.

What the saved file carries

The copy VEIL writes is drawn from pixels into a new PNG, so the camera model, the timestamps and the GPS coordinates in the original do not come with it; the metadata is gone as a side effect of how the file is made, not as a promise. That is worth knowing both ways round: it is why the exported copy is safe to post, and why the original on your phone still has all of it. If you need the original cleaned as well, CLOAK strips the metadata from it, and EXIF shows you what was in there first.

It is a PNG, which is lossless and larger than the JPEG you started with. If the size matters, put it through SHRINK afterwards; the pixelation is already burned in, so nothing comes back.

Video, screenshots and documents

Different jobs, different tools, and using the wrong one is the usual way this goes wrong.

Why it matters that the photo stays here

The photographs people want faces taken out of are, by definition, photographs of identifiable people who did not consent to being posted. Uploading one to a free site to anonymise it puts the un-anonymised version on somebody else's machine, which is the exact thing the edit was for. In several jurisdictions a photograph of an identifiable person is personal data, and handing it to a third-party processor is a decision with a name and a paper trail. Doing it in the tab avoids the question entirely rather than answering it.

The short version