ICO to PNG Converter: Extract Windows Icons, Lossless

An .ico is a container, not a picture. After a short header comes a directory that lists each image packed inside, then the image data. Microsoft built it that way so a single file could hold a 16px taskbar icon, a 32px shortcut icon, and 48px or 256px large versions at once, letting Windows draw whichever size fits the spot. That same multi-size container is what most sites still serve at /favicon.ico. PNG holds exactly one image, so the conversion is really an extraction: one entry comes out of the container and becomes a standalone file. This tool feeds the raw .ico bytes to the browser's own image decoder, the same code that renders icons on a web page. The decoder reads the directory and hands back the entry it judges best, normally the largest, highest-color version present. Those pixels, alpha included, are drawn to a canvas and re-encoded as PNG. PNG uses DEFLATE, which is lossless, so the colors and transparency you see are written out unchanged. The browser picks the entry, not a hand-rolled parser, so the chosen size depends on the icon and your browser, not on a setting here. Everything happens locally. The .ico is read into memory, decoded, and the PNG comes back as a direct download. No upload, no server round trip, and once the page is loaded you can go offline and it still runs. Need a specific smaller size out of a multi-resolution icon? Convert it, then downscale the PNG in any editor, since the smaller entries are separate images the decoder skips over.