Toolnido

Screenshot Redaction: Hide Part of an Image in Your Browser

Cover names, numbers or faces in a screenshot with pixelated blocks or a solid black box. Your image is processed in your browser and never uploaded. Saves a new copy and leaves the original alone.

Your image is processed inside this browser, on a canvas. It is not uploaded and no server ever receives it. The result is a new file; your original is never changed. This hides pixels in the copy only: it is a visual cover, not a guarantee of complete removal, and your original still contains everything, so keep it private or delete it.

1. Choose an image

One image at a time: up to 25 MB, 16 megapixels (for example 4000 x 4000) and 8192 pixels per side. A decoded image needs about 4 bytes per pixel, so a 16 megapixel image uses about 64 MB of memory, and the working copy doubles that. Phones and tablets may run out earlier. Photos are turned upright using their EXIF orientation.

2. Cover

Use a black box for passwords, card numbers, ID numbers and anything a person must never read. There is no soft blur here on purpose: blur can sometimes be partly reversed.

4 to 200. Bigger blocks hide more.

3. Select areas

Click and drag on the image below to select an area. On a phone, tap one corner and then the opposite corner. Or type an area as percentages of the image and press Add area. Up to 50 areas.

When to use this

  • You want to share a screenshot but hide a name, email address, account number or a face.
  • You do not want to upload a sensitive screenshot to a website you do not know.
  • You need a solid cover for something that must stay unreadable, not just a light blur.

How to use

  1. Choose one PNG, JPEG or WebP image.
  2. Pick Pixelate or Black box. Use the black box for passwords, card numbers and ID numbers.
  3. Click and drag on the preview to select an area. On a phone, tap one corner and then the opposite corner. You can also type an area as percentages.
  4. Check the preview, then press Save redacted copy and download the new file.

Examples

Understanding the result

Pixelate splits the selected area into square blocks and replaces each block by its average colour. The block size is a number of pixels, and by default about one eightieth of the longest side of the image. Black box replaces every pixel in the area with opaque black. The copy keeps the file type of the original: PNG stays PNG, JPEG stays JPEG. The image is turned upright using its EXIF orientation first.

Limitations

FAQ

How do I blur part of a screenshot?

Choose the image, drag a box over the part you want to hide, pick Pixelate or Black box and save the copy. This tool pixelates instead of blurring because a mosaic with big blocks is harder to undo.

Is a pixelated area safe to share?

With large enough blocks the text is unreadable, but small blocks can leave clues. For passwords, card numbers and ID numbers use the black box. It is a visual cover, not a guarantee of complete removal.

Is my screenshot uploaded?

No. The image is drawn on a canvas inside your browser and saved from there. There is no upload and no server copy.

Does it change my original file?

No. You get a new file with -redacted in the name. Your original still contains everything, so delete it or keep it private.

Why can I not choose a soft blur?

Soft blur keeps more of the original information than solid blocks and can sometimes be partly reversed with software. A mosaic or a solid box is the safer choice.

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