Image Pixelator

Pixel size is the only parameter that really matters. It sets how many source pixels collapse into one output block. At 22, every block is roughly 22 by 22 source pixels, so a 2200px wide photo becomes about 100 blocks across. Lower it and detail returns; raise it and shapes simplify.

Palette decides the colour count. Original keeps your photo's own colours and only blocks them up. Game Boy maps everything to four greens, NES to a fixed set of 54 colours, Lost Century to a muted 16-colour set. Palette mapping removes gradients, so photos with soft lighting lose depth while illustrations, logos and pixel art gain clarity.

Grid overlay is a display aid, not part of the output. Turn it on when you are judging block size or aligning a selection; switch it off before downloading unless you actually want the lines baked in. There is a separate grid option that does write the grid into the image.

Sometimes only one region needs to change — a face in a group photo, a licence plate, a price tag, an address. Pixelating the whole image to hide one detail destroys the picture.

Drag a rectangle over the area you want to block out in the canvas, then apply. Everything outside the selection is copied through untouched at full detail, so the rest of the photo looks normal and the covered region is unreadable.

For redaction the setting matters more than usual: small blocks can sometimes be reverse-engineered from context, so use a pixel size of 24 or higher when the goal is to make text unreadable, and check the result at 100% zoom before publishing.

A grid over pixel blocks is what turns pixelation from a blur-ish effect into something that reads as deliberate. Two uses: visible grid lines as a design element, and grid as a guide while you work.

For design output, switch the grid option into "bake into image" and pick a line colour that separates the blocks — a slightly darker shade of the image colours works better than pure black, which tends to look heavy at small pixel sizes. Line width should be 1 output pixel, not 1 source pixel, otherwise the grid gets eaten by the downsampling.

For the guide use, leave the grid as an overlay only. This is how you line up a partial selection with block boundaries, so the redacted area does not cut a block in half and leave a half-sharpened edge. If you are preparing an image for tile-based work or a pixel art sprite, the grid overlay is the fastest way to confirm your pixel size matches the target canvas.

No app needed. Open this page in Safari, tap the upload box, and choose Photo Library — the picker gives access to your camera roll without any special permission.

Adjust pixel size with the slider; the preview updates as you drag, so you can judge the result on the actual screen it will be viewed on. When you download, iOS saves the file to Files, and you can move it into Photos from there. If you want it back in the camera roll directly, tap Share on the downloaded file and choose Save Image.

The whole conversion happens on the device, so it works the same on a slow connection and nothing in your camera roll gets uploaded.

No account, no email, no daily quota. The tool is a single page that runs locally, which is why there is nothing to gate behind a login.

The output has no watermark and no resolution cap. What you download is the same size as what you uploaded, with the pixel size you chose applied. Nothing is re-compressed on the way out beyond whatever format you selected.

Because the image never leaves your device, the tool is usable on documents you would not upload elsewhere: ID cards, bank statements, screenshots containing addresses.

Canva's Pixelate is an effect inside its editor. To use it you create a design, upload the image, apply the effect, then export — sensible if you are already laying out a post or a slide.

This tool is a single conversion with no project around it. Two clicks, no account, and it outputs at your original resolution. The parameters are numeric and visible, which matters when you need the same pixel size across a set of images rather than an eyeballed slider.

Where Canva wins is anything involving text, layout or multiple elements on one canvas. If the image is going into a designed page, do it there. If the image is the deliverable, this is faster.