Pixelate Image

This tool pixelates an image — turns it into a mosaic — directly in your browser. The picture is divided into square blocks of the size you choose, every block's pixels are averaged into one flat colour, and the whole block is painted with that average. It is the standard way to obscure a face, a licence plate or a name before sharing a photo or a screenshot, and it is also used for the deliberate mosaic look. Your files are never uploaded to a server.

Block size is the whole control. A block of 2–8 px is a fine mosaic that leaves the picture clearly recognisable; 16–32 px gives the familiar "censored" look; 50–200 px breaks the image into large flat squares that lose individual features. The block grid starts at the top-left corner, so when the width or height is not an exact multiple of the block size the last row and column are narrower — a partial block averages only the pixels that really exist, and nothing outside the image is invented.

Be realistic about what pixelation hides. It is a lossy summary, not a redaction: each block keeps the average of everything underneath it, so a block still leaks something about the original, and the smaller the blocks, the more they leak. Pixelated text has been recovered from screenshots by published tools — Depix is the best-known proof of concept — and light pixelation of large letters often leaves them readable. For anything genuinely sensitive (a password, an account number, an ID), cover the area with a solid box, or make the blocks very large compared with the detail you are hiding. This tool tells you when the block size you have chosen is fine enough to be risky.

Transparency is handled by hand. Colour is averaged weighted by alpha, so a fully transparent pixel cannot darken its neighbours with whatever hidden colour it stores, and the block's opacity is the simple average of its pixels, so a half-transparent area stays half-transparent. PNG and WebP output keep that transparency; JPG cannot, so when you save as JPG any transparent areas are filled with the background colour you pick (white by default).

How it works: your browser decodes each image (a phone photo is turned upright using its EXIF orientation), draws it onto a canvas at full size, and this tool rewrites every block of pixels in JavaScript — not with the canvas filter or a shrink-and-upscale trick, so the blocks are flat and the result is the same in every browser. The canvas is re-encoded and offered as a download. Because the picture is redrawn, EXIF metadata — camera, date and GPS location — is not copied into the result, which is a privacy gain in itself.

Limits: up to 50 images at a time, 50 MB each, and about 100 megapixels (16,384 px per side). PNG output is lossless; JPG and WebP are re-compressed at the quality you set (92 by default). With "Same as input", PNG, JPG and WebP keep their format; GIF, BMP and AVIF are saved as PNG, and an animated file keeps only its first frame. iPhones and iPads allow a canvas of only about 16.7 megapixels, so a very large photo may fail there with a message saying so. Your images stay on your device: the Network tab in your browser's developer tools shows no request carrying them.

1. The file's size is checked (50 MB) before it is read, and its first bytes confirm it is PNG, JPG, WebP, GIF, BMP or AVIF; the browser decodes it upright. 2. The block size is checked: it must be a whole number from 2 to 200, and no larger than the image's longer side. 3. The image is drawn onto a canvas at full size and its RGBA pixels are read. 4. The buffer is tiled from the top-left into blockSize × blockSize squares; the last row and column may be smaller. 5. Each square's colour is the alpha-weighted mean of its pixels — sum(red × alpha) ÷ sum(alpha) for red, and likewise for green and blue — so a transparent pixel does not pull the colour towards its own hidden value. The square's opacity is the plain mean of the alphas. 6. Every pixel in the square is set to that one colour and opacity. 7. For JPG output only, transparent areas have already been composited onto the chosen background colour, because JPG cannot store transparency. 8. The pixels are written back, the canvas is encoded, and the file is named like photo-pixelated.jpg.