Mosaic blocks, region-aware
Pick a block size from 4 px to 80 px. Pixelate just the part you drag, or the whole image when no region is set.
Mosaic-censor a face, name, or any part of an image. Drop a photo, drag a rectangle, slide. Free, no signup.
Drop an image to pixelate
JPG, PNG, WebP, AVIF, GIF, BMP · single file · 50 MB max
Pixelation is the censor of choice when blur is not enough. The chunky-block aesthetic reads as 'intentionally redacted' rather than 'accidentally out of focus.' Court documents use it. News photos use it. Reality shows use it. The visual signal is clear: this part was hidden on purpose.
This tool runs in your browser using two Canvas passes — downscale the region to a small grid, then upscale it back with smoothing disabled. The result is the chunky mosaic familiar from every redacted document. Block size controls how chunky: 4 px is subtle, 32 px is loud, 64 px is the wall-of-blocks effect.
Pixelation at block size of 16 px or higher resists recovery better than light blur. For sensitive numbers — credit cards, IDs, license plates — the chunky mosaic is the safer pick. The original file never leaves your device; the masked version is saved straight from the browser to your downloads folder.
Pick a block size from 4 px to 80 px. Pixelate just the part you drag, or the whole image when no region is set.
Drag as many regions as you need. Every rectangle uses the same block size. Tap the X on any region to remove it.
Drag the slider, the mosaic updates on the same canvas. No apply button to click before you can see the result.
Block out names on a public court filing screenshot before sharing on a forum or blog. Mosaic reads as 'this part was redacted on purpose.'
Posting a candid group shot? Pixelate faces of bystanders before publishing. Chunky blocks signal an intentional decision.
Showing off a fancy new card or proof of identity? Pixelate the number with 16 px+ blocks so it cannot be recovered.
Pixelation at large block sizes doubles as a retro aesthetic. Pick 32 px or 64 px for the bitmap-banner look.
Walkthrough screenshots often include real account details. Pixelate the visible numbers before publishing the tutorial.
Sharing part of a contract or invoice? Pixelate the personal data before posting. Mosaic blocks are the standard 'redacted' visual.
JPG, PNG, WebP, AVIF, GIF, BMP — all decoded in the browser. The file never uploads.
Switch the region toggle to rectangle mode and drag across the area to censor. Adjust the block size — the preview updates as you slide.
Click apply to commit the mosaic to a new PNG, JPG, or WebP. Download saves to your filesystem.
For privacy redaction of numbers, names, or faces — use a block size of 16 px or larger. Smaller blocks can sometimes be partially reconstructed.
For a retro pixel-art look, use larger block sizes (32 px or 64 px) on the whole image rather than a region.
Multiple rectangles all share the same block size. If you need different sizes for different regions, apply once, save, then re-open and apply again with new settings.
Pixelation is more visually distinctive than blur — it signals 'this was censored' rather than 'this happened to be out of focus.' Pick based on the message you want the reader to receive.
Save the original file separately. Once pixelated and saved, the masked region cannot be restored.
Gaussian blur — softer feel than mosaic for non-privacy use.
Crop the image to the area you care about, then pixelate.
Fix orientation before censoring.
Resize before or after pixelation for the right output dimensions.
Re-encode to JPG, PNG, WebP, or AVIF.
Drop the image, drag the area, slide the block size. Download in seconds.