Blur or Pixelate Image Area

How to blur or pixelate part of an image

1. Drop an image on the drop zone, or click it to choose one.
2. Drag on the picture to draw a rectangle over what you want to hide. Draw as many areas as you need: every face, plate or line of text can have its own.
3. Pick the Effect: Pixelate (mosaic), Blur or Solid box. The effect applies to every area, and the preview updates live.
4. Adjust Mosaic / blur size (shown in pixels) until the hidden details are really unreadable, or choose the Box color for a solid box.
5. To adjust an area, drag it to move it or drag its blue corner to resize it. Delete selected area removes the active one, Remove all areas starts over. Add area places a new rectangle in the middle, handy on touch screens or with a keyboard (arrow keys move the selected area, Delete removes it).
6. Choose the Output format and Quality, then click Download image.

Pixelate, blur or solid box?

Pixelate (mosaic) replaces each block of pixels with its average color. It is the classic look for faces on the news. The Mosaic / blur size is a percentage of the picture’s shorter side, so the result looks the same on a phone photo and on a small screenshot.

Blur mixes each pixel with its neighbours, twice, for a soft and natural look that suits backgrounds, crowds and car plates in street photos.

Solid box paints over the area with a flat color. Nothing of the original remains in those pixels.

The effect only uses the pixels inside each area: colors from outside never leak in, and hidden content never bleeds out around the rectangle.

Is blurring or pixelating enough to protect sensitive data?

For faces and scenery, a strong mosaic or blur is usually enough. For text it is not always safe. Pixelation and blur are predictable, deterministic operations: researchers have shown that short text such as a password, an account number or a PIN can sometimes be recovered by pixelating candidate texts in the same font and comparing the blocks, or by “deblurring” a weak blur. Large block sizes make this much harder, but only a Solid box destroys the information completely.

So, for passwords, card numbers, IBANs, addresses, email addresses, QR codes or anything in a screenshot you would regret leaking, use Solid box.

Metadata and privacy

The image is processed in your browser; it is never uploaded. The downloaded file is re-encoded from the pixels, which also removes its metadata: EXIF camera details, the date, and the GPS location that many phones embed in photos. Hiding a face is pointless if the file still says where it was taken.