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Image · 55 tools · nothing uploads

PNG to ICO

Wrap a PNG in an ICO favicon. ICO spends one byte on each dimension, so 256 is the ceiling and a larger logo is scaled down to fit.

Input

PNG to ICO wraps your image in an icon directory whose entry stores each dimension in a single byte, so 256 pixels is the ceiling. Anything smaller is wrapped at the size you gave it. A 600 pixel logo is resampled to 256 first; a 1275 by 625 banner lands at 256 by 125, keeping its shape.

Questions

What is the size limit?

256 pixels on the longest side. An ICO directory entry spends exactly one byte on each dimension, so 256 is the format hard ceiling; a larger logo is scaled down to fit rather than refused.

Does it keep transparency?

Yes. An ICO here is a directory entry wrapped around a PNG, so the same alpha channel a PNG favicon would have survives inside the ICO.

Which engine handles this?

A dedicated ICO wrapper calls the same PNG encoder every lossless target in this matrix uses, at quality 100, then wraps the result in the ICO directory format. This runs in Node, on the command line, through MCP and in the browser.

What size should I expect?

Close to what a same-size PNG would be, since the ICO is a PNG with a small directory header around it, plus any reduction from being scaled down to fit the 256-pixel ceiling.

What is the reverse page?

There is none, and there cannot be one. ICO has no decoder anywhere on this site, by decision, since demand for reading one back out is close to zero next to writing a favicon.

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