Pixelate Image

Pixelate Image paints square blocks over one picture and downloads a PNG of the same pixel size. The block slider opens at 12 and runs from 4 to 40.

The top-left pixel fills the block

The slider is labeled Block size (px). The size used is at least 2 and is the block value rounded down. The canvas width and height stay the photo's width and height. Each block copies the red, green, blue, and alpha of its top-left pixel across the rest of that block, stopping at the image edge. A 100 by 50 picture at block 12 stays 100 by 50. Twelve divides 96, so the last columns are a 4-pixel remainder, and the last rows are a 2-pixel remainder. Those short blocks still use their own top-left pixel. There is no face detector and no brush. The whole picture is blocked.

What the mosaic does not hide by itself

A block of 4 still leaves a recognizable shape on a large portrait. A block of 40 is coarse. Neither setting blurs only a face. Blur Image is a different control. The download name ends in pixelate-image.png, using the original base name, or the word image when the file has no name. The button says Download PNG. A missing file shows Please upload an image. The button stays disabled until a preview exists. EXIF is whatever the browser applied when it decoded the file. A JPEG source comes back as PNG.

Remainder columns

Because the loop steps by the block size, an edge that is not a multiple of the block is a smaller rectangle, not a stretched one. At block 40, a 100-pixel width is two full blocks and a 20-pixel remainder. The remainder is not filled with the previous block's color. It samples its own corner. If you need the blocks to land evenly, crop the photo to a multiple of the block before you download. This page does not crop for you. Block 12 on a 96 by 48 picture has no remainder, because both sides divide by 12. The color sample is still the corner pixel, so a block that starts on a bright speck paints that whole square bright. Block 4 divides a 100 pixel width evenly.

The picture stays here

This browser paints the mosaic on a canvas. The photo is not uploaded. A large file stays large, because the pixel count does not drop. The PNG can be heavier than a JPEG source. Keep the original if the mosaic is only a preview you might undo. Changing the slider and downloading again uses the block that is selected at that moment. Block 4 on a 100 by 50 picture still leaves the canvas at 100 by 50, with twenty-five full columns and a zero remainder because 100 divides by 4. Block 8 leaves a 4 pixel remainder on that width, because 12 times 8 is 96. The remainder rule is the same at every step of the slider.