oakenbitHow to redact an image
- Click Choose an image, drop a photo onto the box, or copy a screenshot and press Ctrl+V (Cmd+V on a Mac) on this page.
- Pick an effect: Black box, Pixelate or Blur.
- Drag across everything you want to hide. Each area is covered as soon as you let go. Drag an area to move it; choosing another effect changes the selected area.
- Check the whole image once more, then click Download redacted image. The original file on your device is not changed.
Which effect is safe for text?
Use the black box for text and numbers. A solid box replaces every pixel in the area with black, so nothing of the original is left in the saved file.
Pixelation and blur are fine for faces, backgrounds or a licence plate in a holiday photo, but they are not reliable for text. Both keep averages of the original pixels, and researchers have published methods that guess pixelated or blurred text by trying candidate texts in the same font until the pixel pattern matches. This works best on short, predictable strings such as passwords, account numbers and amounts in a screenshot. Large pixel blocks make it much harder, but a box makes it impossible.
| Effect | What happens to the pixels | Use it for |
|---|---|---|
| Black box | Replaced with solid black. Nothing remains. | Text, numbers, signatures, QR codes, anything sensitive |
| Pixelate | Each block becomes the average colour of its pixels. | Faces and objects where a softer look matters |
| Blur | Each pixel becomes a weighted average of its neighbours inside the area. | Backgrounds and incidental details |
Unlike some editors, this tool does not lay a shape over the image in a separate layer: the pixels underneath are changed before the file is saved, so the cover cannot be removed afterwards.
What happens to the metadata
Photos from phones often contain the GPS location, the time and the camera model. The redacted image is drawn into a new file, which contains none of that metadata. The picture is turned upright first, so photos that a phone stored sideways are saved the right way up. If you only want to remove metadata without changing the picture, use the photo metadata remover, which keeps the image data byte for byte.
Frequently asked questions
- Is my image uploaded?
- No. The tool runs in your browser. You can check it in the Network tab of your browser's developer tools or use the page offline once it has loaded.
- Which format should I save in?
- PNG for screenshots and documents: it is lossless and keeps text sharp. JPEG for photos, where it makes much smaller files (saved at 92% quality). The format of the original does not matter.
- Does it work on a phone?
- Yes. Choose a photo from your gallery and drag with your finger to cover an area.
- Can I redact a PDF?
- Not with this tool. A PDF can hide text under images and in layers; take a screenshot of the page and redact that, or use a PDF editor that has a real redaction function.
- Can someone undo the redaction?
- Not for black boxes: the pixels are gone from the saved file. For pixelated or blurred text, see which effect is safe.
- What does it cost?
- Nothing. There are no ads, no sign-up and no limits apart from very large images (over 50 megapixels).