ICO to PNG Converter

How the ICO to PNG Converter works

Windows .ico icon files can bundle several image frames at different sizes — commonly 16×16, 32×32, 48×48, and 256×256 — inside a single container, so the operating system can pick the sharpest one for each context (taskbar, desktop, Alt-Tab switcher). Each frame is stored either as a PNG-compressed block (used for larger, high-color frames since Windows Vista) or as a raw BMP DIB with an XOR color layer and an AND transparency mask (the legacy format used by older, smaller icons).

This tool reads the ICONDIR header and each ICONDIRENTRY directly from the file's bytes, detects which storage format each frame uses by checking for the PNG signature, decodes raw BMP frames (1-, 4-, 8-, 24-, and 32-bit) pixel-by-pixel including the transparency mask, and renders every frame to a canvas so you can preview and download any of them as a standalone PNG. By default the largest available frame is selected first, since that preserves the most detail. Everything happens locally in your browser — the .ico file never leaves your device.