How the blur tool works
The tool opens your photo in the browser and lets you choose what to hide. You can blur, pixelate or censor the whole image, only the parts you select, or everything except the parts you select. Nothing is uploaded: the photo is changed and saved on your own device, which matters for the kind of pictures people usually blur.
- Selected areas: drag rectangles or ellipses over faces, license plates, house numbers, name tags or screens. For odd shapes, paint over them with the brush. Each area can be moved, resized and deleted, and you can add as many as you need.
- Whole image: blurs or pixelates everything, for a soft background picture, a teaser or a placeholder.
- Background: keeps your selection sharp and blurs the rest, so a person or a product stands out from a busy scene.
Undo and Redo work for every step, from a new area to a changed setting, and Ctrl+Z or Cmd+Z does the same on a keyboard. The preview is drawn at screen size to stay quick, but the download is made from the full image, so the saved file has exactly the same width and height in pixels as your original.
Blur, pixelate or solid box
| Effect | What it does | Good for |
|---|---|---|
| Blur | Mixes each pixel with its neighbors, like an out of focus lens | Background blur, bystanders in a crowd, a soft look |
| Pixelate | Turns square blocks into one average color, the mosaic look | Faces and license plates in photos you share |
| Solid box | Covers the area with one flat color | Text that must stay secret: passwords, account and ID numbers, addresses, signatures |
The strength and the block size grow with the image, so a setting looks the same on a small screenshot and on a large camera photo. The labels show what that means in pixels for your image. Judge the result in the preview: if you can still tell who a face belongs to or make out a letter, raise the setting or switch to Solid box.
How safe is blurring?
Blur and pixelation remove detail, but they do not always remove information. Studies have shown that hidden content can sometimes be recovered:
- Steven Hill, Zhimin Zhou, Lawrence Saul and Hovav Shacham showed in the paper On the (In)effectiveness of Mosaicing and Blurring as Tools for Document Redaction (Proceedings on Privacy Enhancing Technologies, 2016) that redacted text could be recovered with statistical models, and concluded that mosaicing and blurring are not viable ways to redact text.
- Richard McPherson, Reza Shokri and Vitaly Shmatikov described in Defeating Image Obfuscation with Deep Learning (2016) how trained neural networks recognized faces, objects and handwritten digits in images protected by mosaicing and by blurring.
Text is the weak spot: the first paper recovered redacted text with statistical models and tested its method across many typefaces and font sizes. That leads to simple advice:
- For any text that must stay secret, use Solid box. It replaces the pixels with one color, so there is nothing left to work with.
- If you blur or pixelate, use a strong setting: a high strength or large blocks. A light blur that still shows the shape of the letters hides little.
- Cover a little more than the sensitive part, so no edge of a letter or a face peeks out.
- Check the result at full size before you share it, and keep in mind that other photos of the same scene can give away what you hid.
Blurring the background
Choose Background under Apply to, then draw around the subject: an ellipse fits a head and shoulders, a rectangle fits a product, and the brush follows any outline. You can combine several shapes, for example an ellipse for the face and brush strokes for the arms. Everything outside them is blurred; the selection keeps every original pixel. A strong blur gives the look of a shallow depth of field, a light one just calms a busy scene. To cut a subject out completely instead, use the background remover.
Formats and quality
With Save as set to Original, a JPG stays a JPG, a PNG stays a PNG and a WebP stays a WebP. GIF and BMP files are saved as PNG, HEIC photos from an iPhone and AVIF files as JPG. PNG is lossless, so every pixel outside your areas stays exactly as it was. JPG and WebP are compressed again with the quality you set, 92 by default, which is hard to tell apart from the original. Phone photos open upright, and the saved copy carries no EXIF data, so the camera details and GPS location are not copied. To check that before sharing, use the EXIF viewer and remover, and to add your name to a photo instead, use Add Watermark.
How to use the blur tool
- 1Drop a photo on the box, choose it from your device, or paste an image.
- 2Choose what to apply the effect to: selected areas, the whole image, or the background.
- 3Drag rectangles or ellipses, or paint with the brush, over the parts to hide or keep. Move, resize or delete them as needed.
- 4Pick Blur, Pixelate or Solid box and set the strength, then download the image at full size.
Frequently asked questions
How do I blur part of a picture?
Open the photo, keep Apply to on Selected areas and drag a rectangle or an ellipse over the part you want to hide, such as a face or a license plate. Use the brush for odd shapes. Every area can be moved, resized or deleted, and Undo takes back the last step. Then press Download.
Is blurring or pixelating safe for hiding text?
Not always. Researchers have shown that text hidden by pixelation or blur can sometimes be read again, especially when the blur is light, the blocks are small and the font is known. For passwords, account numbers, addresses or anything else that must stay secret, use Solid box, which replaces the pixels with one color and leaves nothing behind.
What is the difference between blur and pixelate?
Blur mixes each pixel with its neighbors, which gives a soft, out of focus look. Pixelate replaces square blocks with their average color, which gives a mosaic look. Both hide details, and both hide more at a higher setting. Solid box hides everything.
How do I blur the background and keep the person sharp?
Set Apply to Background, then draw an ellipse or a rectangle around the person, or paint over them with the brush. Everything outside your selection is blurred and the selection stays sharp. Raise the strength for a stronger effect.
Does the saved photo keep its full size?
Yes. The preview is drawn smaller to stay fast, but the download is made from the full image, so it has exactly the same width and height in pixels as your original. Pixels outside the areas you chose are left as they were. JPG and WebP files are compressed again with the quality you set; PNG is lossless.
Can someone undo the blur in my downloaded image?
The saved file contains only the blurred or pixelated pixels, not the original ones, and no layers or undo steps. What can sometimes be guessed is the content itself, from what is left of it, which is why Solid box is the safe choice for text. Your original file on your device is not changed.
Are my photos uploaded?
No. Your browser opens the photo, applies the blur and saves the new file on your own device. Nothing is sent to a server, which matters most for exactly the kind of pictures people blur.