Posterize Image

How Posterize Image works

Reduce an image to a handful of colour levels for a poster effect. Posterisation quantises each channel, which creates flat bands of colour. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

Five levels per channel

Each channel is rounded to one of five evenly spaced values — 0, 64, 128, 191, 255. The result is a flat, screen-printed look with a maximum of 125 distinct colours instead of millions.

Because each channel quantises independently, colours that were nearly identical snap to the same value and large areas become uniform, which is exactly what makes the style read as deliberate.

Good sources and bad sources

Photos with strong shapes and simple lighting posterize well. Gradient skies and skin tones do not: a smooth gradient becomes a set of hard bands, and faces turn patchy.

If the bands are ugly, the fix is to increase contrast first so the source has fewer distinct tones to begin with.

Saving it

PNG is the right output: flat colour areas compress extremely well losslessly, and JPG would add ringing exactly along the hard edges where the effect is visible.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions