Real privacy redaction
Averaging each block into a single flat colour destroys the underlying detail, so it genuinely hides faces, number plates, names and documents rather than merely softening them.
Pixelate Image (Mosaic)
Block out faces, plates and text with an adjustable mosaic pixelation.
- Upload
- Single file · 25 MB max
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
Loading tool…
The tool is loading its code on your device. This happens once and is cached for later visits.
Processed entirely on your device
Your file is read, transformed and re-encoded inside this browser tab using JavaScript. There is no upload endpoint — nothing leaves your machine, nothing is stored, and the result is created as a local object URL that disappears when you close the page.
Overview
About the Pixelate Image (Mosaic)
Pixelate an image free online to add a mosaic blur for privacy redaction or a retro effect. Adjustable block size, in your browser with CollabsTool. No upload.
How pixelation works
Pixelation divides the image into square blocks and replaces every pixel in a block with that block's average colour. The result is a coarse mosaic where fine detail is gone but overall shapes and colours remain. Larger blocks mean fewer, chunkier squares and more destroyed detail.
Redacting faces, plates and text
The most common use is privacy: hiding a face in a crowd photo, blurring a number plate, or masking names and account numbers in a screenshot. Because each block collapses to a single flat colour, the underlying information is genuinely removed rather than merely softened, which is why mosaic is the standard censoring look.
The retro mosaic look
With smaller blocks, pixelation becomes a style — the chunky, low-resolution aesthetic of early video games and glitch art. It is a quick way to make a thumbnail, avatar or graphic feel deliberately lo-fi while keeping the full canvas dimensions.
Runs on your device
The block averaging happens on an in-browser canvas and is exported as a lossless PNG, so private images are censored locally and never transmitted anywhere.
Step by step
How to use the Pixelate Image (Mosaic)
Drop an image onto the upload area.
Raise the block-size slider; the picture breaks into coarse mosaic squares.
Use a large block size to make faces, plates or text unreadable.
Download the pixelated PNG at full original resolution.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Retro 8-bit aesthetic
Small block sizes give the chunky, low-resolution mosaic look used in game art, thumbnails and stylised graphics without reducing the actual file dimensions.
Private and instant
Pixelation is computed per block on a local canvas and exported as PNG, so sensitive images are censored without ever being uploaded.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
Is pixelating enough to protect privacy?
For casual redaction, yes — a coarse mosaic removes the detail needed to recognise a face or read text. For legally sensitive material, crop or black out the region instead, since very large mosaics can sometimes be partially reconstructed.
What block size should I use?
8-16 px reads as a stylish retro mosaic. 20-40 px is heavy enough to hide identifiable features. Judge at full size, not in the thumbnail.
Is this the same as blurring?
No. A blur smears pixels smoothly; pixelation snaps each block to one flat colour, which is more effective at destroying detail and gives a distinct blocky look.