Pixelate Image
Add a mosaic/pixelation effect to obscure details or create pixel art
100% Private: All processing happens in your browser. Your files never leave your device.
This tool creates the classic mosaic look by drawing your photo onto a tiny canvas first, then stretching that tiny canvas back up to full size with smoothing turned off, so each shrunken pixel becomes a visible flat-colored block. The Block Size slider (2px to 80px, default 10) controls how small that intermediate canvas is: a low value keeps most of the detail, a high value throws most of it away. The preview canvas redraws instantly as you move the slider, at a smaller on-screen size than the final download for speed, but the block pattern you see there is the same pattern the full-resolution download will have.
There's no face detection, no brush, and no selection box — the effect always covers the entire photo at once. If you only want to obscure one person in a group shot or one object in a wider scene, crop down to that area first with /image/crop, pixelate the crop, and treat that as your finished redacted piece rather than expecting this tool to find and isolate a region on its own. The output format also depends on what you upload: a PNG comes back as a PNG with transparency intact, but anything else is flattened onto a white background first and saved as a JPEG.
How it works
1. Drop or browse a photo
One image at a time. Anything over 20 MB is turned away at this step with a message naming the file and the 20 MB limit.
2. Drag the Block Size slider
Runs from 2px (labeled Subtle) to 80px (labeled Heavy), starting at 10px. The preview canvas updates on every move.
3. Press Apply & Download
This doesn't save the file right away — it renders the mosaic at your photo's full original resolution first, and the button then turns into a second Download Pixelated Image button. Press that to actually get the file.
4. Start Over for a different photo or setting
Clears the loaded image and puts the Block Size slider back to its default of 10px.
When you'd use it
Hiding a face before posting publicly
Crop tightly to just the face with /image/crop, then run the crop through this tool at a high block size before sharing the photo on a forum, marketplace listing, or social post.
Blocking a plate, ID number, or address in a photo
Crop to the sensitive region and mosaic it out rather than trying to pixelate a small area within a full, unedited scene.
Making a retro pixel-art thumbnail
A low-to-moderate block size on a bright, simple photo gives a chunky 8-bit look that works well as an avatar or a stylized thumbnail.
Hiding a QR code or barcode before sharing a photo
A pixelated code can no longer be scanned by a phone camera, which is useful when a code visible in the background of a photo shouldn't be reused by whoever sees it.
How the mosaic effect is actually drawn
The tool draws your image onto a canvas sized down by the block-size value, with image smoothing switched on for that first pass, then draws that small canvas back onto itself at full size with smoothing switched off. That off-smoothing upscale is what produces flat, hard-edged blocks instead of a blur — each shrunken pixel simply gets stretched into a square rather than blended with its neighbors.
Because the same math scales the block size to match the smaller preview canvas, what you see while dragging the slider is a faithful, just-smaller-on-screen version of what the full-resolution download will look like — there's no surprise once you press Apply.
Transparency and the output format
The exported file follows one rule: a PNG source stays a PNG, transparency and all, while every other format is flattened onto a white background first and then saved as a JPEG at 95% quality — so a semi-transparent WEBP or a GIF with see-through pixels comes back as a plain white-backed JPG rather than keeping its original format or its transparency.
Choosing a block size that actually obscures detail
The default of 10px gives a fairly light mosaic that's closer to a stylized effect than genuine redaction — enough detail can survive at low values that a familiar face might still be recognizable. If the goal is to reliably hide something rather than stylize it, push the slider well past the middle of its range; the resize step at higher values discards far more of the original detail, and there's no way to recover it from the finished image alone.
Frequently asked questions
Is the default block size enough to make a face unrecognizable?
Not necessarily. At 10px, the default, enough shape and color can survive that a familiar face may still be identifiable. For genuine redaction, move the slider well past the middle of its 2-80px range.
Does pressing Apply & Download save the file right away?
No. It processes the image at full resolution first, then the button changes to Download Pixelated Image — you need to press that second button to actually get the file.
Can I pixelate just one face and leave the rest of the photo sharp?
No, the effect always covers the whole image. Crop down to the area you want hidden with /image/crop first, then pixelate that crop.
What happens to a transparent image when I pixelate it?
A PNG keeps its transparency. Any other format — JPG, WEBP, GIF — is filled with white behind the image first and exported as a JPEG, so transparent areas come back white.
Is there a file size limit on the photo I upload?
Yes, 20 MB per image, checked the moment you drop or select the file, before any pixelation happens.
Why did my WEBP or GIF download as a JPG?
The tool only preserves the PNG format for PNG uploads. Every other input format is converted to JPEG on export, which is also why any transparency in a WEBP or GIF doesn't survive.