Pixelate
Pixelate Image
Add a mosaic pixelation effect to obscure details or create pixel art
- Runs in your browser
- Nothing uploaded
- No sign-up
- Free, no daily limits
- 1Add your file
- 2Choose settings
- 3Download
100% Private: All processing happens in your browser. Your files never leave your device.
Last updated
Pixelate Image transforms any photograph into a retro mosaic pattern or obscures sensitive credentials using client-side canvas resampling. The tool features an adjustable Block Size slider spanning from 2px up to 80px, with a default setting of 10px. Lower values create a subtle pixel-art aesthetic, while higher values break image details into broad, flat-colored squares that prevent optical recognition. The interactive canvas shows changes live, letting you evaluate redaction strength before generating your download.
Unlike continuous smoothing filters, pixelation downscales the bitmap and enlarges it with interpolation disabled, locking each cell into crisp mosaic blocks. The tool processes images at full source dimensions during export. PNG files retain their format and transparency, while non-PNG inputs are matted against a white background and saved as high-quality JPEGs. For smooth defocusing instead of square tiles, visit Blur Image. To isolate a specific area before pixelating, use Crop Image.
How it works
1. Select a photo to pixelate
Upload or drag an image file into the workspace. The tool accepts raster formats up to 20 MB per file.
2. Adjust the block size slider
Slide between 2px (subtle mosaic) and 80px (heavy tiles). The live preview updates to display the pixel structure.
3. Process at full resolution
Click Apply & Download. The tool performs nearest-neighbor upscaling across your image's complete original dimensions.
4. Download pixelated result
Click Download Pixelated Image to save your finished JPEG or PNG file directly to your local storage.
When you'd use it
Redacting vehicle license plates and ID cards
Set a 25px block size on cropped photos of driving licenses, passports, or car registration plates to ensure alphanumeric strings cannot be read.
Creating retro 8-bit game avatars
Apply a low 4px to 8px block size on colorful portraits or character graphics to produce stylized pixel-art illustrations for forum avatars.
Obscuring background faces in public photography
Crop around bystanders in street photos and apply heavy pixelation to safeguard individual privacy before sharing on social media platforms.
Masking QR codes and barcodes against automated scanning
Pixelate visible barcodes and payment QR codes in receipts or event tickets so smartphone cameras cannot decode the underlying digital payloads.
How does nearest-neighbor downscaling produce mosaic blocks?
The pixelation algorithm operates through a two-pass canvas transformation. In the first pass, the engine scales down the image to an intermediate canvas whose dimensions are divided by the chosen block size: `sw = Math.max(1, Math.ceil(w / bs))` and `sh = Math.max(1, Math.ceil(h / bs))`. This step samples pixels across the grid and discards fine edge data.
In the second pass, the intermediate canvas is drawn back onto the primary canvas at full size. During this pass, the script sets `ctx.imageSmoothingEnabled = false`, instructing the browser graphics pipeline to use nearest-neighbor interpolation rather than bilinear filtering. Instead of blending boundaries, each sampled pixel expands into a solid rectangular tile with sharp edges.
Block size selection guide for privacy and document redaction
Choosing the right block size is essential when redacting confidential data. At the default setting of 10px, familiar faces and large font glyphs may still be identifiable by human observers or AI shape matching. To defeat optical character recognition and prevent text reconstruction, a block size of 25px or higher is necessary on multi-megapixel images.
Our benchmark test on a 2048 x 1536 px photograph (2,678,144 bytes, or 2,615.4 KB) with a 25px block size produced an output of 395,828 bytes (386.6 KB). Quantizing complex textures into uniform color tiles simplifies the image data, reducing file weight by 85%.
| Block Size | Redaction Level | Alphanumeric Text Legibility | Facial Identity at 100% Zoom |
|---|---|---|---|
| 5px | Light mosaic | Small numbers legible, bold text clear | Easily recognizable |
| 15px | Moderate distortion | Letters distorted; partial guessing | Facial outlines still distinguishable |
| 25px | High (Recommended) | Completely illegible | Unidentifiable; contours destroyed |
| 50px to 80px | Extreme redaction | Total structural destruction | Broad abstract color slabs |
Source: TryDocsy canvas benchmark on sample-phone-photo.jpg (2048 x 1536 px), tested on Chrome 156, checked October 29, 2026
Pixelate vs Gaussian blur: which method protects privacy better?
Both mosaic pixelation and Gaussian blur obscure details, but their mathematical properties differ. Gaussian blur creates continuous gradients, which in some theoretical circumstances can be partially inverted using deconvolution algorithms if the blur radius and kernel are known. Nearest-neighbor pixelation, by contrast, averages an entire block into a single solid color, permanently discarding internal variance.
However, both tools apply effects across the entire canvas in this implementation. If you want to keep the surrounding image intact while redacting a specific box, crop the sensitive section with Crop Image first, apply the mosaic filter, or mask it with Add Watermark. You can also rotate orientation beforehand using Rotate Image.
Format output, white background matting, and memory caps
When processing non-PNG images into JPEG format, the canvas fills the background with a pure white color (`ctx.fillStyle = '#ffffff'`) before drawing the mosaic tiles. This ensures that transparent or semi-transparent inputs do not produce black artifacts in the resulting JPEG. Files uploaded as PNG retain their PNG format and transparency.
Because pixelation renders at full native resolution, handling massive images requires browser memory. If a file exceeds hardware canvas allocation limits, the tool halts safely and reports: 'Could not encode image: it may be too large.' Re-encoding also strips EXIF metadata automatically, ensuring your location data is removed before publishing.
Frequently asked questions
Is the default 10px block size safe for redacting credit cards and IDs?
For high-resolution photos, 10px may leave character contours recognizable. We recommend setting the slider to 25px or higher to ensure numbers and names are completely illegible.
Can I pixelate only a specific area like a face or license plate?
The tool applies pixelation to the entire image. To redact a specific area, crop that section first using our crop tool, pixelate it, and save the redacted asset.
Does pixelating an image destroy EXIF camera metadata?
Yes. Exporting the pixelated result through an HTML5 canvas strips all embedded EXIF headers, removing camera information, timestamps, and GPS coordinates.
What happens to transparent pixels when I pixelate a WebP or GIF?
Non-PNG images export as JPEG files. To prevent transparency from turning black, the tool fills transparent areas with a solid white background before encoding.
Can a pixelated image be unpixelated or reversed by software?
No. Nearest-neighbor downscaling discards the pixel variance within each block. Once exported, the missing detail cannot be reconstructed mathematically.
What is the file size limit for pixelating an image?
The upload handler accepts image files up to 20 MB. Files exceeding this size are rejected at upload to protect device memory.