Image Mosaic
Pixelate a region of an image to hide faces, text or details.
Region in pixels (leave empty for the whole image)
Pixelation runs on a canvas in your browser. The image never leaves your device.
How to use it
- Choose an image up to 10MB - JPEG, PNG or WebP.
- Enter the region in pixels: X, Y, width and height. Leave the fields empty to mosaic the whole image.
- Drag the block size slider - larger blocks hide more detail.
- Click Download to save the result as a PNG.
Common use cases
- Redacting documents - cover account numbers, addresses or names before sharing a scan.
- Blurring a face - pixelate a person in a crowd shot when a soft blur is not enough.
- Before and after reveals - hide an answer or result in a quiz or game screenshot.
Why it stays private
Pixelation runs on a canvas element inside your browser tab. The file is read through a local object URL and never sent anywhere, so redacted documents stay under your control.
FAQ
Q: How do I find the right pixel coordinates? A: Open the image in any viewer that shows cursor coordinates, or estimate from the dimensions shown in the status line after you load the file.
Q: Is the mosaic reversible? A: No. Each block is replaced by its average color, so the original pixels inside the region are gone from the output.
Q: Why did the whole image get pixelated? A: That happens when the region fields are empty or zero. Fill in a width and height to limit the effect to one area.
Your data stays on this device
Image Mosaic runs 100% locally. Everything you paste or drop is processed by your own browser and never transmitted. Nothing is stored on our servers — close the tab and it is gone.
Nothing you type is sent to a server, logged, or used for analytics. The page works even with your network disconnected after first load.