Pixelate an Image Online (Mosaic Effect)
Blur or pixelate selected parts of a photo by drawing rectangles over them — locally in your browser.
Processed entirely in your browser — nothing you enter here is ever uploaded.
Result
About this tool
This page opens the blur tool with the pixelate mode already selected — drop in your photo, drag rectangles over the areas you want to turn into mosaic and download the result.
Pixelation replaces each block inside your selection with its average color, producing the classic censor mosaic. The block size slider controls how coarse the mosaic is: small blocks soften details, large blocks make text and faces completely unreadable. You can also pixelate the whole photo with one click for a retro low-resolution effect.
Prefer a smooth haze instead of squares? Switch the mode to blur in the same tool. Everything runs locally in your browser, so your photos never leave your device.
Example. A rectangle drawn in pixelate mode rewrites only the pixels inside that rectangle into square blocks.
Limit. Regions are axis-aligned rectangles; there is no freehand or oval mask.